Method of preparing poly(alkylene carbonate) via copolymerization of carbon dioxide/epoxide in the presence of novel complex

ABSTRACT

Provided is a method of preparing poly(alkylene carbonate) using a molecular weight regulator in a process of preparing a copolymer of carbon dioxide/epoxide using a novel complex synthesized from salen-type ligand including a quaternary ammonium salt as a catalyst. According to the present invention, even though the molecular weight regulator is used, an activity of the catalyst may be stably maintained, whereby the low molecular weight of poly(alkylene carbonate) having a desirable level may be effectively provided. In addition, it is expected that since the novel complex as the catalyst of the present invention has a simple structure as compared to the existing copolymerization catalyst, due to the economical preparation cost thereof, the novel complex may be effectively applied to a large-scale commercial process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/777,861, filed on Sep. 17, 2015 now U.S. Pat. No. 9,969,842, which isthe United States national phase of International Application No.PCT/KR2014/002321 filed Mar. 20, 2014, and claims priority to KoreanPatent Application No. 10-2013-0030179 filed Mar. 21, 2013, thedisclosures of which are hereby incorporated in their entirety byreference.

BACKGROUND OF INVENTION Technical Field

The present invention relates to a method of preparing poly(alkylenecarbonate) using a molecular weight regulator in a process of preparinga copolymer of carbon dioxide/epoxide using a novel complex synthesizedfrom a salen-type ligand including a quaternary ammonium salt as acatalyst.

Background Art

Poly(alkylene carbonate) is an easily biodegradable polymer and isuseful for packaging or coating materials. Methods of preparingpoly(alkylene carbonate) from an epoxide compound and carbon dioxide ishighly eco-friendly in that they use no phosgene which is harmfulcompound and adopt easily available and inexpensive carbon dioxide.

Since 1960's, many researchers have developed various types of catalyststo prepare poly(alkylene carbonate) from an epoxide compound and carbondioxide. Recently, a catalyst having high activity and high selectivityand synthesized from a salen:([H₂salen=N,N′-bis(3,5-dialkylsalicylidene)-1,2-ethylenediamine]-typeligand including a quaternary ammonium salt has been published [KoreanPatent Registration No. 10-0853358 (Registration Date: Aug. 13, 2008);Korean Patent Application No. 10-2008-0015454 (Filing Date: Feb. 20,2008); PCT/KR2008/002453 (Filing Date: Apr. 30, 2008); J. Am. Chem. Soc.2007, 129, 8082-8083 (Jul. 4, 2007); Angew. Chem. Int. Ed. 2008, 47,7306-7309 (Sep. 8, 2008)]. The catalyst disclosed in Korean PatentRegistration No. 10-0853358 shows high activity and high selectivity,and may provide a copolymer having a large molecular weight and may bepolymerized at a high temperature to be applicable to commercialprocesses. Furthermore, this catalyst is advantageous because aquaternary ammonium salt is contained in the ligand, and thus thecatalyst may be easily separated from a copolymer resulting fromcopolymerization of carbon dioxide and epoxide, and re-used.

Also, the inventor of Korean Patent Registration No. 10-0853358 havecarefully examined a structure of a particular catalyst having higheractivity and higher selectivity among the catalyst group disclosed inthe above patent, and have proved that such a catalyst has a peculiarstructure in which a nitrogen atom of the salen ligand is notcoordinated to a metal but an oxygen atom thereof only is coordinatedthereto, which was not known until now (see Structure 1 below, Inorg.Chem. 2009, 48, 10455-10465).

Furthermore, a method of easily synthesizing the ligand of the compoundof Structure 1 has been developed (Bull. Korean Chem. Soc. 2009, 30,745-748).

High molecular weight poly(alkylene carbonate) may be economicallyprepared using the compound of Structure 1 as a highly active catalyst.However, since poly(alkylene carbonate) has a low glass transitiontemperature (which is 40° C. in the case of poly(alkylene carbonate)prepared from propylene oxide and carbon dioxide) and has insufficientmechanical strength, predetermined limitations are imposed on theapplications that may be developed therewith.

With the goal of overcoming the limitations of poly(alkylene carbonate),methods of preparing poly(alkylene carbonate)polyol having low molecularweight and a plurality of —OH terminal groups and preparing polyurethanetherefrom have been developed. Polyurethane is a polymer obtained byreacting a compound having an —OH group with a compound having anisocyanate (—NCO) group thus forming a urethane bond (—NHC(O)O—). Avariety of compounds having an —NCO group and compounds having an —OHgroup are being developed, and thermoplastic or thermosetting plasticsor elastomeric polyurethanes having various physical properties havebeen developed and used. Polyurethane was prepared and used in an amountof about twelve million tons all over the world as of 2007, and theamount thereof is increased by 5% per year and the applications thereofhave become wide. Examples of the compound having an —OH group includediols and polyester diols having —OH terminal groups, which havethousands of molecular weights obtained by ring-opening polymerizationof ethylene oxide or propylene oxide. Attempts have been made to preparepoly(alkylene carbonate)diol or polyol rather than poly(alkyleneoxide)diol or polyester diol to thereby attain polyurethane (W. Kuran,Polymeric Materials Encyclopedia, J. C. Salamone, Ed. CRC Press, Inc.,Boca Raton 1996, Vol. 9, p. 6623; Polymer, 1992, vol 33, 1384-1390).Polyurethane prepared from poly(alkylene carbonate)polyol is known tohave higher hydrolyzability compared to urethane prepared from polyesterpolyol (EP 302712; U.S. Pat. No. 5,863,627), and is also reported tohave greater antistatic effects (U.S. Pat. No. 4,931,486). Furthermore,thrombus coagulation resistance is reported to be high (WO 9857671).

EP 302712 (priority date: Aug. 4, 1987) and EP 311278 (priority date:Oct. 6, 1987) disclose polycarbonate diol prepared by condensingdiethylcarbonate (EtOC(O)OEt) and 1,6-hexanediol or 1,5-petandediol, andpreparation of polyurethane using the same. In addition, U.S. Pat. No.5,171,830 (filing date: Aug. 16, 1991) discloses a method ofsynthesizing poly(alkylene carbonate) by condensing dialkyl carbonate(ROC(O)OR) and alpha, omega-alkanediol having 4 or more carbons in thepresence of a base catalyst and preparation of a urethane resin usingthe same.

EP 798328A2 (priority date: Mar. 28, 1996) discloses synthesis ofpolycarbonate-co-polyether diol using condensation of polyether diol anddimethylcarbonate (MeOC(O)OMe).

Also, synthesis of poly(alkylene carbonate)macrodiol using condensationof various diols and ethylene carbonate and preparation of polyurethaneusing the same are disclosed in Journal of Applied Polymer Science,1998, 69, 1621-1633 and Journal of Applied Polymer Science, 1989, 37,1491-1511.

However, such poly(alkylene carbonate)polyol is not prepared usingcopolymerization of carbon dioxide and epoxide and also has a differentstructure from that of a copolymer of carbon dioxide and epoxide.Specifically, in order to prepare poly(alkylene carbonate) usingpolycondensation of ethylene carbonate or dialkyl carbonate, diol havingspaced 3 or more carbons should be used. That is, poly(alkylenecarbonate) has a structure in which a carbonate bond is linked by 3 ormore carbons. Poly(alkylene carbonate) prepared by copolymerization ofcarbon dioxide and epoxide has a structure in which a carbonate bond islinked by 2 carbons.

U.S. Pat. No. 4,686,276 (filing date: Dec. 30, 1985) discloses a methodof synthesizing poly(ethylene carbonate)diol by copolymerizing carbondioxide and ethylene oxide in the presence or absence of ethylenecarbonate using a diol compound as an initiator and a catalystconsisting of an alkaline compound and a tin compound. In addition. U.S.Pat. No. 4,528,364 (filing date: Apr. 19, 1984) discloses a method ofremoving a catalyst from the prepared polymer compound. Here, theprepared polymer has carbon dioxide content less than 30%, which is nota complete alternating copolymer. In addition, preparation ofpolyurethane using poly(ethylene carbonate)diol which was prepared andpurified by the above method is disclosed in Journal of Applied PolymerScience, 1990, 41, 487-507.

EP 0222453 (filing date: Jun. 11, 1986) discloses a method ofsynthesizing polyol by copolymerizing carbon dioxide and epoxide using adouble metal cyanide compound as a catalyst and using an organicmaterial having reactive hydrogen as a molecular weight regulator.However, the obtained polyol has a carbon dioxide content of 5 to 13 mol%, which is not a pure poly(alkylene carbonate) compound based oncomplete alternating copolymerization of carbon dioxide and epoxide.

CN Patent No. 1060299A (filing date: Sep. 19, 1991), which is publishedlater, discloses a method of preparing polyol by copolymerizing carbondioxide and epoxide using a polymer-supported bimetallic catalyst andusing an organic material having 1 to 10 reactive hydrogen as amolecular weight regulator. However, the polyol prepared by Examples hasa carbon dioxide content of 37 to 40 mol %, which is not a purepoly(alkylene carbonate) compound based on complete alternatingcopolymerization of carbon dioxide and epoxide.

U.S. Pat. No. 8,247,520 (filing date: Sep. 8, 2009) discloses a methodof copolymerizing carbon dioxide and epoxide using a chain transferagent which is a molecular weight regulator under a binary catalystsystem of (salen)Co complex. However, the present inventors found thatas an amount of the used chain transfer agent becomes increased in thecopolymerization system, catalyst system activity is deteriorated, suchthat there is a limitation in obtaining low molecular weight ofcopolymer having desirable level.

As described above, synthesis of low molecular weight of poly(alkylenecarbonate) by copolymerization of carbon dioxide/epoxide in the presenceof a molecular weight regulator has been abundantly reported. Meanwhile,in order to prepare appropriate poly(alkylene carbonate) having lowmolecular weight in a large-scale commercial process, since maintenanceof catalyst system activity in the preparation process as well aseconomical cost of copolymerization catalyst system are important,development of a novel catalyst system capable of satisfying therequirements has been demanded.

SUMMARY OF THE INVENTION Technical Problem

An object of the present invention is to provide a method of preparinglow molecular weight of poly(alkylene carbonate) using a molecularweight regulator in a process of preparing a copolymer of carbon dioxideand epoxide using a novel complex synthesized from salen-type ligandincluding a quaternary ammonium salt as a catalyst.

Another object of the present invention is to provide a method in whichan activity of the catalyst is effectively maintained in the preparationprocess by using the novel complex as the copolymerization catalyst inthe process of preparing the low molecular weight of poly(alkylenecarbonate).

Solution to Problem

In one general aspect, a method of preparing poly(alkylene carbonate)comprises:

copolymerizing carbon dioxide and one or more epoxide compounds selectedfrom a group consisting of (C2-C20)alkylene oxide substituted orunsubstituted with halogen, (C1-C20)alkyloxy, (C6-C20)aryloxy or(C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; (C4-C20)cycloalkylene oxidesubstituted or unsubstituted with halogen, (C1-C20)alkyloxy,(C6-C20)aryloxy or (C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; and(C8-C20)styrene oxide substituted or unsubstituted with halogen,(C1-C20)alkyloxy, (C6-C20)aryloxy, (C6-C20)ar(C1-C20)alkyl(aralkyl)oxyor (C1-C20)alkyl in the presence of the following compound representedby Chemical Formula 9 which is a molecular weight regulator, using thefollowing complex represented by Chemical Formula 1 as a catalyst.

[In Chemical Formula 1,

M is trivalent cobalt or trivalent chromium;

A is an oxygen or sulfur atom;

Q is a diradical that connects two nitrogen atoms;

R¹ to R¹⁰ are each independently hydrogen; halogen; (C1-C20)alkyl;(C1-C20)alkyl containing one or more selected from among halogen,nitrogen, oxygen, silicon, sulfur and phosphorus; (C2-C20)alkenyl;(C2-C20)alkenyl containing one or more selected from among halogen,nitrogen, oxygen, silicon, sulfur and phosphorus;(C1-C20)alkyl(C6-C20)aryl; (C1-C20)alkyl(C6-C20)aryl containing one ormore selected from among halogen, nitrogen, oxygen, silicon, sulfur andphosphorus; (C6-C20)aryl(C1-C20)alkyl; (C6-C20)aryl(C1-C20)alkylcontaining one or more selected from among halogen, nitrogen, oxygen,silicon, sulfur and phosphorus; (C1-C20)alkoxy; (C6-C30)aryloxy; formyl;(C1-C20)alkylcarbonyl; (C6-C20)arylcarbonyl; a metalloid radical ofGroup 14 metal substituted with hydrocarbyl; a protonated group of thefollowing Chemical Formula 2; a protonated group of the followingChemical Formula 3; a protonated group of the following Chemical Formula4; a protonated group of the following Chemical Formula 5; a protonatedgroup of the following Chemical Formula 6; or a protonated group of thefollowing Chemical Formula 7; two of R¹ to R¹⁰ may be linked with eachother by a protonated group of the following Chemical Formula 8 tothereby form a ring:

wherein at least two or more of R¹ to R¹⁰ are a protonated groupselected from a group consisting of the following Chemical Formulas 2,3, 4, 5, 6 and 7; or two of R¹ to R¹⁰ are linked with each other by aprotonated group of the following Chemical Formula 8 to thereby form aring;

X⁻ is a halogen anion; a (C6-C20)aryloxy anion; a (C6-C20)aryloxy anioncontaining one or more selected from among a halogen atom, a nitrogenatom, an oxygen atom, a silicon atom, a sulfur atom and a phosphorusatom; a (C1-C20)alkylcarboxyl anion; a (C1-C20)alkylcarboxyl anioncontaining one or more selected from among a halogen atom, a nitrogenatom, an oxygen atom, a silicon atom, a sulfur atom and a phosphorusatom; a (C6-C20)arylcarboxyl anion; a (C6-C20)arylcarboxyl anioncontaining one or more selected from among a halogen atom, a nitrogenatom, an oxygen atom, a silicon atom, a sulfur atom and a phosphorusatom; a (C1-C20)alkoxy anion; a (C1-C20)alkoxy anion containing one ormore selected from among a halogen atom, a nitrogen atom, an oxygenatom, a silicon atom, a sulfur atom and a phosphorus atom; a(C1-C20)alkylcarbonate anion; a (C1-C20)alkylcarbonate anion containingone or more selected from among a halogen atom, a nitrogen atom, anoxygen atom, a silicon atom, a sulfur atom and a phosphorus atom; a(C6-C20)arylcarbonate anion; a (C6-C20)arylcarbonate anion containingone or more selected from among a halogen atom, a nitrogen atom, anoxygen atom, a silicon atom, a sulfur atom and a phosphorus atom; a(C1-C20)alkylsulfonate anion; a (C1-C20)alkylsulfonate anion containingone or more selected from among a halogen atom, a nitrogen atom, anoxygen atom, a silicon atom, a sulfur atom and a phosphorus atom; a(C1-C20)alkylamido anion; a (C1-C20)alkylamido anion containing one ormore selected from among a halogen atom, a nitrogen atom, an oxygenatom, a silicon atom, a sulfur atom and a phosphorus atom; a(C6-C20)arylamido anion; a (C6-C20)arylamido anion containing one ormore selected from among a halogen atom, a nitrogen atom, an oxygenatom, a silicon atom, a sulfur atom and a phosphorus atom; a(C1-C20)alkylcarbamate anion; a (C1-C20)alkylcarbamate anion containingone or more selected from among a halogen atom, a nitrogen atom, anoxygen atom, a silicon atom, a sulfur atom and a phosphorus atom; a(C6-C20)arylcarbamate anion; or a (C6-C20)arylcarbamate anion containingone or more selected from among a halogen atom, a nitrogen atom, anoxygen atom, a silicon atom, a sulfur atom and a phosphorus atom;

X⁻ may be coordinated to M:

Y₁ ⁻ is F⁻, Cl⁻, Br⁻, I⁻, BF₄ ⁻, ClO₄ ⁻, NO₃ ⁻ or PF₆ ⁻;

Y₂ ⁻² is SO₄ ⁻² or CO₃ ⁻²;

a is an integer obtained by adding 1 to the total number of monovalentcations included in protonated groups of R¹ to R¹⁰;

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=a is satisfied;

Z₁, Z₃, Z₄, Z₅, Z₆, Z₇, Z₈, Z₉, Z₁₁ and Z₁₂ are each independently annitrogen atom or a phosphorus atom;

Z₂ and Z₁₀ are each independently an oxygen atom, a sulfur atom or amethylene group (—CH₂—);

n is an integer of 1 to 10, preferably 1 to 5;

m is an integer of 1 to 10, preferably 1 to 5;

R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷, R⁴¹, R⁴²,R⁴³, R⁴⁴, R⁴⁵, R⁵¹, R⁵², R⁵³, R⁵⁴, R⁵⁵, R⁶¹, R⁶², R⁶³, R⁶⁴, R⁶⁵, R⁶⁶,R⁶⁷, R⁷¹, R⁷, R⁷³ and R⁷⁴ are each independently hydrogen;(C1-C20)alkyl; (C1-C20)alkyl containing one or more selected from amonghalogen, nitrogen, oxygen, silicon, sulfur and phosphorus;(C2-C20)alkenyl; (C2-C20)alkenyl containing one or more selected fromamong halogen, nitrogen, oxygen, silicon, sulfur and phosphorus;(C1-C20)alkyl(C6-C20)aryl; (C1-C20)alkyl(C6-C20)aryl containing one ormore selected from among halogen, nitrogen, oxygen, silicon, sulfur andphosphorus; (C6-C20)aryl(C1-C20)alkyl; (C6-C20)aryl(C1-C20)alkylcontaining one or more selected from among halogen, nitrogen, oxygen,silicon, sulfur and phosphorus; or a metalloid radical of Group 14 metalsubstituted with hydrocarbyl; two of R¹¹, R¹², R¹³, R¹⁴ and R¹⁵, two ofR²¹, R²², R²³, R²⁴, R²⁵, R²⁶ and R²⁷, two of R⁴¹, R⁴², R⁴³, R⁴⁴ and R⁴⁵,two of R⁵¹, R⁵², R⁵³, R⁵⁴ and R⁵⁵, two of R⁶¹, R⁶², R⁶³, R⁶⁴, R⁶⁵, R⁶⁶and R⁶⁷ or two of R⁷¹, R⁷², R⁷³ and R⁷⁴ may be linked with each other tothereby form a ring; and

R³¹, R³² and R³³ are each independently (C1-C20)alkyl; (C1-C20)alkylcontaining one or more selected from among halogen, nitrogen, oxygen,silicon, sulfur and phosphorus; (C2-C20)alkenyl; (C2-C20)alkenylcontaining one or more selected from among halogen, nitrogen, oxygen,silicon, sulfur and phosphorus; (C1-C20)alkyl(C6-C20)aryl;(C1-C20)alkyl(C6-C20)aryl containing one or more selected from amonghalogen, nitrogen, oxygen, silicon, sulfur and phosphorus;(C6-C20)aryl(C1-C20)alkyl; (C6-C20)aryl(C1-C20)alkyl containing one ormore selected from among halogen, nitrogen, oxygen, silicon, sulfur andphosphorus; or a metalloid radical of Group 14 metal substituted withhydrocarbyl; two of R³¹, R³² and R³³ may be linked with each other tothereby form a ring.]J(LH)_(c)  [Chemical Formula 9]

[In Chemical Formula 9, J is C1 to C60 hydrocarbyl c-valent radical withor without an ether group, an ester group or an amine group; LH is —OHor —CO₂H; and c is an integer from 1 to 10, in which LH may be identicalor different when c is 2 or more.]

Since the complex represented by Chemical Formula 1 structurallyincludes at least 2 or more onium salts in a molecule, the complex usedas a catalyst has excellent activity and promotes polymerization even ata relatively low temperature. In addition, the complex represented byChemical Formula 1 includes the form in which one or two or more oniumsalts symmetrically present at both sides based on a central metal,respectively, such that preparation yield of the complex may beimproved.

Preferably, in the complex represented by Chemical Formula 1, Q may be(C6˜C30)arylene, (C1˜C20)alkylene, (C2˜C20)alkenylene,(C2˜C20)alkynylene or (C3˜C20)cycloalkylene, more preferably,1,2-cyclohexylene, phenylene or ethylene, and most preferably,trans-1,2-cyclohexylene.

Preferably, in the complex represented by Chemical Formula 1, M may betrivalent cobalt, and A may be oxygen.

Preferably, in the complex represented by Chemical Formula 1, R¹ to R¹⁰may be each independently hydrogen; halogen; (C1-C20)alkyl;(C1-C20)alkyl containing one or more selected from among halogen,nitrogen, oxygen, silicon, sulfur and phosphorus; (C2-C20)alkenyl;(C2-C20)alkenyl containing one or more selected from among halogen,nitrogen, oxygen, silicon, sulfur and phosphorus;(C1-C20)alkyl(C6-C20)aryl; (C1-C20)alkyl(C6-C20)aryl containing one ormore selected from among halogen, nitrogen, oxygen, silicon, sulfur andphosphorus; (C6-C20)aryl(C1-C20)alkyl; (C6-C20)aryl(C1-C20)alkylcontaining one or more selected from among halogen, nitrogen, oxygen,silicon, sulfur and phosphorus; (C1-C20)alkoxy; (C6-C30)aryloxy; formyl;(C1-C20)alkylcarbonyl; (C6-C20)arylcarbonyl; a metalloid radical ofGroup 14 metal substituted with hydrocarbyl; a protonated group of thefollowing Chemical Formula 2; a protonated group of the followingChemical Formula 3; a protonated group of the following Chemical Formula4; a protonated group of the following Chemical Formula 5; a protonatedgroup of the following Chemical Formula 6; or a protonated group of thefollowing Chemical Formula 7; two of R¹ to R¹⁰ may be linked with eachother by a protonated group of the following Chemical Formula 8 tothereby form a ring; wherein at least two or more of R¹, R², R⁵ and R⁶are a protonated group selected from a group consisting of the followingChemical Formulas 2, 3, 4, 5, 6 and 7; or two of R¹, R², R⁵ and R⁶ arelinked with each other by a protonated group of the following ChemicalFormula 8 to thereby form a ring.

More preferably, in the complex represented by Chemical Formula 1, R³,R⁴, R⁷, R⁸, R⁹ and R¹⁰ are each hydrogen, R¹, R², R⁵ and R⁶ are eachindependently hydrogen; halogen; (C1-C20)alkyl; (C1-C20)alkyl containingone or more selected from among halogen, nitrogen, oxygen, silicon,sulfur and phosphorus; (C2-C20)alkenyl; (C2-C20)alkenyl containing oneor more selected from among halogen, nitrogen, oxygen, silicon, sulfurand phosphorus; (C1-C20)alkyl(C6-C20)aryl; (C1-C20)alkyl(C6-C20)arylcontaining one or more selected from among halogen, nitrogen, oxygen,silicon, sulfur and phosphorus; (C6-C20)aryl(C1-C20)alkyl:(C6-C20)aryl(C1-C20)alkyl containing one or more selected from amonghalogen, nitrogen, oxygen, silicon, sulfur and phosphorus;(C1-C20)alkoxy; (C6-C30)aryloxy; formyl; (C1-C20)alkylcarbonyl;(C6-C20)arylcarbonyl; a metalloid radical of Group 14 metal substitutedwith hydrocarbyl; a protonated group of the following Chemical Formula2; a protonated group of the following Chemical Formula 3; a protonatedgroup of the following Chemical Formula 4; a protonated group of thefollowing Chemical Formula 5; a protonated group of the followingChemical Formula 6; or a protonated group of the following ChemicalFormula 7; two of R¹, R², R⁵ and R⁶ may be linked with each other by aprotonated group of the following Chemical Formula 8 to thereby form aring; wherein at least two or more of R¹, R², R⁵ and R⁶ are a protonatedgroup selected from a group consisting of Chemical Formulas 2, 3, 4, 5,6 and 7; or two of R¹, R², R⁵ and R⁶ are linked with each other by aprotonated group of Chemical Formula 8 to thereby form a ring.

More preferably, the present invention provides a method of preparingpoly(alkylene carbonate), comprising:

copolymerizing carbon dioxide and one or more epoxide compounds selectedfrom a group consisting of (C2-C20)alkylene oxide substituted orunsubstituted with halogen, (C1-C20)alkyloxy, (C6-C20)aryloxy or(C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; (C4-C20)cycloalkylene oxidesubstituted or unsubstituted with halogen, (C1-C20)alkyloxy,(C6-C20)aryloxy or (C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; and(C8-C20)styrene oxide substituted or unsubstituted with halogen,(C1-C20)alkyloxy, (C6-C20)aryloxy, (C6-C20)ar(C1-C20)alkyl(aralkyl)oxyor (C1-C20)alkyl in the presence of the compound represented by ChemicalFormula 9 using a complex having the following structure represented byChemical Formula 10 or 11 as a catalyst.

[In Chemical Formula 10,

R⁸¹ and R⁸² identically represent methyl, ethyl, isopropyl, ortert-butyl; or a protonated group identically selected from a groupconsisting of Chemical Formula 2. Chemical Formula 3, Chemical Formula4. Chemical Formula 5, Chemical Formula 6 and Chemical Formula 7;

R⁸³ and R⁸⁴ identically represent methyl, ethyl, isopropyl, ortert-butyl; or a protonated group identically selected from a groupconsisting of Chemical Formula 2, Chemical Formula 3, Chemical Formula4, Chemical Formula 5, Chemical Formula 6 and Chemical Formula 7;

with the proviso that a case where R⁸¹ and R⁸² identically representmethyl, ethyl, isopropyl, or tert-butyl; and simultaneously R⁸³ and R⁸⁴identically represent methyl, ethyl, isopropyl, or tert-butyl isexcluded;

X₁ ⁻ is a halogen anion; a (C1-C20)alkylcarboxyl anion; a(C1-C20)alkylcarboxyl anion containing one or more selected from among ahalogen atom, a nitrogen atom, an oxygen atom, a silicon atom, a sulfuratom and a phosphorus atom; a (C1-C20)alkylcarbonate anion; a(C1-C20)alkylcarbonate anion containing one or more selected from amonga halogen atom, a nitrogen atom, an oxygen atom, a silicon atom, asulfur atom and a phosphorus atom; a (C1-C20)alkylcarbamate anion; or a(C1-C20)alkylcarbamate anion containing one or more selected from amonga halogen atom, a nitrogen atom, an oxygen atom, a silicon atom, asulfur atom and a phosphorus atom;

X₁ ⁻ may be coordinated to Co;

Y₁ ⁻ is Cl⁻, Br⁻, BF₄ ⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²;

a is an integer obtained by adding 1 to the total number of monovalentcations included in protonated groups of R⁸¹ to R⁸⁴; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=a is satisfied.]

[In Chemical Formula 11,

R⁸⁵ and R⁸⁶ identically represent methyl, ethyl, isopropyl, ortert-butyl; or are linked with each other by a protonated group ofChemical Formula 8 to thereby form a ring;

R⁸⁷ and R⁸⁸ identically represent methyl, ethyl, isopropyl, ortert-butyl; or are linked with each other by a protonated group ofChemical Formula 8 to thereby form a ring:

with the proviso that a case where R⁸⁵ and R⁸⁶ identically representmethyl, ethyl, isopropyl, or tert-butyl; and simultaneously R⁸⁷ and R⁸⁸identically represent methyl, ethyl, isopropyl, or tert-butyl isexcluded;

X₂ ⁻ is a halogen anion; a (C1-C20)alkylcarboxyl anion; a(C1-C20)alkylcarboxyl anion containing one or more selected from among ahalogen atom, a nitrogen atom, an oxygen atom, a silicon atom, a sulfuratom and a phosphorus atom; a (C1-C20)alkylcarbonate anion; a(C1-C20)alkylcarbonate anion containing one or more selected from amonga halogen atom, a nitrogen atom, an oxygen atom, a silicon atom, asulfur atom and a phosphorus atom; a (C1-C20)alkylcarbamate anion; or a(C1-C20)alkylcarbamate anion containing one or more selected from amonga halogen atom, a nitrogen atom, an oxygen atom, a silicon atom, asulfur atom and a phosphorus atom:

X₂ ⁻ may be coordinated to Co;

Y₃ ⁻ is Cl⁻, Br⁻, BF₄ ⁻ or NO₃ ⁻;

Y₄ ⁻² is SO₄ ⁻²;

e is an integer obtained by adding 1 to the total number of monovalentcations included in protonated groups of R⁸⁵ to R⁸⁸; and

f is an integer of 1 or more, g is an integer of 0 or more, h is aninteger of 0 or more, and f+g+2h=e is satisfied.]

Most preferably, the present invention provides a method of preparingpoly(alkylene carbonate), comprising:

copolymerizing carbon dioxide and one or more epoxide compounds selectedfrom a group consisting of (C2-C20)alkylene oxide substituted orunsubstituted with halogen, (C1-C20)alkyloxy, (C6-C20)aryloxy or(C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; (C4-C20)cycloalkylene oxidesubstituted or unsubstituted with halogen, (C1-C20)alkyloxy,(C6-C20)aryloxy or (C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; and(C8-C20)styrene oxide substituted or unsubstituted with halogen,(C1-C20)alkyloxy, (C6-C20)aryloxy, (C6-C20)ar(C1-C20)alkyl(aralkyl)oxyor (C1-C20)alkyl in the presence of the compound represented by ChemicalFormula 9 using a complex having a structure represented by one of thefollowing Chemical Formulas 12 to 21 as a catalyst.

Since the complex having a structure represented by one of the followingChemical Formulas 12 to 21 includes one or two onium salt(s)symmetrically present at both sides based on a central metal (two orfour onium salts are entirely present in the molecule of the complex),respectively, preparation yield of the complex may be more improved,which is the most preferred.

[In Chemical Formula 12,

R⁹¹ is methyl, ethyl, isopropyl or tert-butyl;

R⁹² is (C1-C20)alkyl;

Z₁₃ is an oxygen atom, a sulfur atom or a methylene group (—CH₂—);

n is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co:

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=3 is satisfied.]

[In Chemical Formula 13,

R⁹³ is methyl, ethyl, isopropyl or tert-butyl;

R⁹⁴, R⁹⁵ and R⁹⁶ are each independently (C1-C20)alkyl;

n is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co:

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=5 is satisfied.]

[In Chemical Formula 14,

R⁹⁷ is methyl, ethyl, isopropyl or tert-butyl;

R⁹⁸, R⁹⁹ and R¹⁰⁰ are each independently (C1-C20)alkyl;

n is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co;

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=3 is satisfied.]

[In Chemical Formula 15,

R¹⁰¹ is methyl, ethyl, isopropyl or tert-butyl;

R¹⁰², R¹⁰³, R¹⁰⁴, R¹⁰⁵ and R¹⁰⁶ are each independently (C1-C20)alkyl;

n is an integer of 1 to 10, preferably 1 to 5;

m is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co;

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=5 is satisfied.]

[In Chemical Formula 16,

R¹⁰⁷ is methyl, ethyl, isopropyl or tert-butyl;

R¹⁰⁸ and R¹⁰⁹ are each independently (C1-C20)alkyl;

n is an integer of 1 to 10, preferably 1 to 5;

m is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co;

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=3 is satisfied.]

[In Chemical Formula 17,

R¹¹⁰ is methyl, ethyl, isopropyl or tert-butyl;

R¹¹¹, R¹¹² and R¹¹³ are each independently (C1-C20)alkyl;

n is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co;

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=3 is satisfied.]

[In Chemical Formula 18,

R¹¹⁴ is methyl, ethyl, isopropyl or tert-butyl;

R¹¹⁵ is (C1-C20)alkyl;

Z₁₄ is an oxygen atom, a sulfur atom or a methylene group (—CH₂—);

n is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co:

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=3 is satisfied.]

[In Chemical Formula 19,

R¹¹⁶ is methyl, ethyl, isopropyl or tert-butyl;

R¹¹⁷, R¹¹⁸ and R¹¹⁹ are each independently (C1-C20)alkyl;

Z₁₅ is an oxygen atom, a sulfur atom or a methylene group (—CH₂—);

n is an integer of 1 to 10, preferably 1 to 5;

m is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co;

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=5 is satisfied.]

[In Chemical Formula 20,

Z₁₆ is an oxygen atom, a sulfur atom or a methylene group (—CH₂—);

n is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co;

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=5 is satisfied.]

[In Chemical Formula 21,

R¹²⁰ is methyl, ethyl, isopropyl or tert-butyl;

R¹²¹ is hydrogen, methyl, ethyl, isopropyl or tert-butyl;

n is an integer of 1 to 10, preferably 1 to 5;

X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻);

X⁻ may be coordinated to Co:

Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;

Y₂ ⁻² is SO₄ ⁻²; and

b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=3 is satisfied.]

In addition, in the compound represented by Chemical Formula 9 which isa molecular weight regulator, a compound in which c is 1; and J is C1 toC60 hydrocarbyl radical with or without an ether group, an ester group,or an amine group may be used as a molecular weight regulator.

In addition, in the compound represented by Chemical Formula 9, acompound in which c is 2; and J is C1 to C60 hydrocarbyl diradical withor without an ether group, an ester group, or an amine group may be usedas a molecular weight regulator, and specifically, the compound may beselected from a compound in which the structure of the compoundrepresented by Chemical Formula 9 is J(CO₂H)₂ (J is —[CR₂]_(n)— (n is aninteger from 0 to 20; and R which may be identical or differentrepresents hydrogen, methyl, ethyl, propyl or butyl), para-phenylene,meta-phenylene, ortho-phenylene or 2,6-naphthalenediyl), or a compoundin which the structure of the compound represented by Chemical Formula 9is J(OH)₂ (J is —[CR₂]_(n)— (n is an integer from 0 to 20; and R whichmay be identical or different represents hydrogen, methyl, ethyl, propylor butyl), —CH₂CH₂N(R)CH₂CH₂— (R is C1-C20 hydrocarbyl), or—[CH₂CH(R)O]_(n)CH₂CH(R)— (n is an integer from 0 to 10; and R ishydrogen or methyl)), or a compound in which the structure of thecompound represented by Chemical Formula 9 is OH—C₆H₄—CO₂H.

In addition, in the compound represented by Chemical Formula 9, acompound in which c is 3; and J is a C1-C60 hydrocarbyl triradical withor without an ether group, an ester group or an amine group may be usedas a molecular weight regulator, and specifically, an example of thecompound may include a compound in which the structure of the compoundrepresented by Chemical Formula 9 is J(CO₂H)₃ (J is 1,2,3-propanetriyl,1,2,3-benzenetriyl, 1,2,4-benzenetriyl or 1,3,5-benzenetriyl.

Further, in the compound represented by Chemical Formula 9, a compoundin which c is 4; and J is a C1-C60 hydrocarbyl tetraradical with orwithout an ether group, an ester group or an amine group may be used asa molecular weight regulator, and specifically, an example of thecompound may include a compound in which the structure of the compoundrepresented by Chemical Formula 9 is J(CO₂H)₄ (1,2,3,4-butanetetrayl or1,2,4,5-benzenetetrayl).

In addition, specific examples of the compound represented by ChemicalFormula 9 may include adipic acid, ethanol, caproic acid, succinic acid,ethylene glycol, diethylene glycol, N-phenyl diethanol amine,4-hydroxybenzoic acid, 1,2,3-propane tricarboxylic acid, 1,2,4-benzenetricarboxylic acid or 1,2,3,4-butanetetracarboxylic acid, and the like.

Specific examples of the epoxide compound in the preparation methodaccording to the present invention include ethylene oxide, propyleneoxide, butene oxide, pentene oxide, hexene oxide, octene oxide, deceneoxide, dodecene oxide, tetradecene oxide, hexadecene oxide, octadeceneoxide, butadiene monoxide, 1,2-epoxide-7-octene, epifluorohydrin,epichlorohydrin, epibromohydrin, isopropyl glycidyl ether, butylglycidyl ether, tert-butyl glycidyl ether, 2-ethylhexyl glycidyl ether,allyl glycidyl ether, cyclopentene oxide, cyclohexene oxide, cycloocteneoxide, cyclododecene oxide, alpha-pinene oxide, 2,3-epoxidenorbornene,limonene oxide, dieldrin, 2,3-epoxidepropylbenzene, styrene oxide,phenylpropylene oxide, stilbene oxide, chlorostilbene oxide,dichlorostilbene oxide, 1,2-epoxy-3-phenoxypropane, benzyloxymethyloxyrane, glycidyl-methylphenyl ether, chlorophenyl-2,3-epoxidepropylether, epoxypropyl methoxy phenyl ether, biphenyl glycidyl ether,glycidyl naphthyl ether, and the like.

The epoxide compound may be used in polymerization using an organicsolvent as a reaction medium, and examples of the solvent includealiphatic hydrocarbons such as pentane, octane, decane, cyclohexane, andthe like, aromatic hydrocarbons such as benzene, toluene, xylene, andthe like, and halogenated hydrocarbons such as chloromethane, methylenechloride, chloroform, carbon tetrachloride, 1,1-dichloroethane,1,2-dichloroethane, ethylchloride, trichloroethane, 1-chloropropane,2-chloropropane, 1-chlorobutane, 2-chlorobutane,1-chloro-2-methylpropane, chlorobenzene, bromobenzene, and the like,which may be used alone or in combination of two or more thereof. Morepreferably, bulk polymerization using a monomer itself as a solvent maybe performed.

In the preparation method of the present invention, a molar ratio of theepoxide compound to catalyst may range from 500 to 1,000,000, preferablyfrom 1,000 to 200,000. In addition, a molar ratio of the catalyst to themolecular weight regulator may range from 1 to 3,000, preferably from 5to 2,000. In the preparation method of the present invention, pressureof carbon dioxide may be up to 100 bar, preferably, 5 bar to 50 bar. Inthe preparation method of the present invention, polymerizationtemperature may be from 10° C. to 120° C., preferably, 20° C. to 90° C.

The poly(alkylene carbonate) prepared by the preparation method of thepresent invention has a number average molecular weight (M_(n)) of 1,000to 100,000 and a molecular weight distribution (that is. M_(w)/M_(n),PDI) of 1.0 to 3.0. Here, M_(n) indicates a number average molecularweight measured by GPC with calibration using polystyrene having asingle molecular weight distribution as a standard material, andmolecular weight distribution M_(w)/M_(n) indicates a ratio between aweight average molecular weight and a number average molecular weightspecified by GPC using the same method.

Meanwhile, since the preparation method of the present invention ischaracterized by using the novel complex as the catalyst, as anotherembodiment of the present invention, poly(alkylene carbonate) havinghigh molecular weight may be prepared by copolymerization of carbondioxide/epoxide only in the presence of the novel complex withoutaddition of the molecular weight regulator.

The maximum turnover number (TON) which is capable of being implementedby the catalyst used in the preparation method of the present inventionis about 10,000.

The poly(alkylene carbonate) prepared by the preparation method of thepresent invention may be preferably represented by the followingChemical Formula 22, and here, the —OH terminal group may be used toprepare polyurethane.J[L-{CR¹³¹R¹³²—CR¹³³R¹³⁴—OC(O)O}_(d)—CR¹³¹R¹³²—CR¹³³R¹³⁴—OH]_(c)  [ChemicalFormula 22]

[In Chemical Formula 22,

L is —O— or —CO₂—;

c is an integer of 2 to 10, L may be identical or different;

J is C1-C60 hydrocarbyl c-valent radical with or without an ether group,an ester group or an amine group;

R¹³¹ to R¹³⁴ are each independently hydrogen; (C1-C10)alkyl substitutedor unsubstituted with halogen or (C1-C20)alkoxy; (C6-C12)arylsubstituted or unsubstituted with halogen or (C1-C20)alkoxy and may belinked with each other to thereby form a ring; and

a value obtained by multiplying d by c is a natural number of 1000 orless.]

In other words, in the polymer compound represented by Chemical Formula22, c is 2; J is C1-C60 hydrocarbyl diradical with or without an ethergroup, an ester group or an amine group; R¹³¹ to R¹³⁴ are eachindependently hydrogen or methyl; d is an integer of 5 to 500, andpreferably, all of R¹³¹ to R¹³⁴ may be hydrogen or all of R¹³¹ to R¹³³may be hydrogen and R¹³⁴ may be methyl(in some repeated units, R¹³¹ ismethyl, and all of the remaining R¹³² to R¹³⁴ are hydrogen).

The polymer compound represented by Chemical Formula 22 may bepreferably a compound in which c is 2; L is —CO₂—; J is —[CR₂]_(n)— (nis an integer of 0 to 20; R which may be identical or differentrepresents hydrogen, methyl, ethyl, propyl or butyl), para-phenylene,meta-phenylene, ortho-phenylene or 2,6-naphthalenediyl, or a compound inwhich c is 2; L is —O—; J is —[CR₂]_(n)— (n is an integer of 0 to 20; Rwhich may be identical or different represents hydrogen, methyl, ethyl,propyl or butyl). —CH₂CH₂N(R)CH₂CH₂— (R is C1 to C20 hydrocarbyl) or—[CH₂CH(R)O]_(n)CH₂CH(R)— (n is an integer of 0 to 10; and R is hydrogenor methyl).

In other words, in the polymer compound represented by Chemical Formula22, c is 3; J is C1-C60 hydrocarbyl diradical with or without an ethergroup, an ester group or an amine group; R¹³¹ to R¹³⁴ are eachindependently hydrogen or methyl; d is a natural number of 330 or less,and preferably, all of R¹³¹ to R¹³⁴ may be hydrogen or all of R¹³¹ toR¹³³ may be hydrogen and R¹³⁴ may be methyl(in some repeated units, R¹³¹is methyl, and all of the remaining R¹³² to R¹³⁴ are hydrogen).

The polymer compound represented by Chemical Formula 22 is preferably acompound in which c is 3; L is —CO₂—; and J is 1,2,3-propanetriyl,1,2,3-benzenetriyl, 1,2,4-benzenetriyl or 1,3,5-benzenetriyl.

In other words, in the polymer compound represented by Chemical Formula22, c is 4; J is C1-C60 hydrocarbyl diradical with or without an ethergroup, an ester group or an amine group; R¹³¹ to R¹³⁴ are eachindependently hydrogen or methyl; d is a natural number of 250 or less,and preferably, all of R¹³¹ to R¹³⁴ may be hydrogen or all of R¹³¹ toR¹³³ may be hydrogen and R¹³⁴ may be methyl(in some repeated units, R¹³¹is methyl, and all of the remaining R¹³² to R¹³⁴ are hydrogen).

The polymer compound represented by Chemical Formula 22 is preferably acompound in which c is 4; L is —CO₂—; and J is 1,2,3,4-butanetetrayl or1,2,4,5-benzenetetrayl.

In the case where the polymer compound in which c is 3 or 4, which is astar shaped polymer having three or four branches, is used to preparepolyurethane, it may induce cross-linking and thus may be employed inpreparation of thermosetting polyurethane.

The low molecular weight poly(alkylene carbonate) polymer prepared bythe preparation method of the present invention may be used itself in acoating material, and the like, and may also be used in a blend withother polymers.

Advantageous Effects of Invention

The present invention provides the method of preparing low molecularweight of poly(alkylene carbonate) by copolymerization of carbon dioxideand epoxide using the molecular weight regulator in the presence of thenovel complex, such that even though the molecular weight regulator isused, the activity of the catalyst may be stably maintained, whereby thelow molecular weight of poly(alkylene carbonate) having a desirablelevel may be effectively provided.

In addition, it is expected that since the novel complex as the catalystof the present invention has a simple structure as compared to theexisting copolymerization catalyst, due to the economical preparationcost thereof, the novel complex may be effectively applied to alarge-scale commercial process.

Further, since the novel complex of the present invention structurallyincludes at least two or more onium salts in a molecule, the complexused as a catalyst may have excellent activity and promotepolymerization even at a relatively low temperature. In particular, inthe case in which one or two or more onium salt(s) are symmetricallypresent at both sides based on a central metal, respectively, thepreparation yield of the complex may be improved.

In addition, it is expected that the low molecular weight ofpoly(alkylene carbonate) prepared by the preparation method of thepresent invention may be effectively used even in preparingpolyurethane.

DESCRIPTION OF THE INVENTION

Hereinafter, the following Examples and Comparative Examplesspecifically describe the effect of the present invention. However,Examples below are not intended to limit the scope of the presentinvention but only to exemplify the present invention.

The catalyst used in the present invention was prepared as shown below.

[Preparation Example 1] Synthesis of Compound 6

A symmetrical cobalt-salen catalyst 6 containing ammonium salt preparedby the following method was prepared.

4-tert-butyl phenol (10.1 g) was put into a mixture of paraformaldehyde(13 g), triethylamine (35 mL), magnesium chloride (9.5 g) andacetonitrile (300 mL), followed by stirring at 55° C. for 3 hours. 2Nhydrochloric acid aqueous solution was put into the reaction mixture toterminate the reaction and the aqueous solution layer was extracted withdichloromethane three times. An organic layer was separated and driedover magnesium sulfate, followed by filtration, and a solvent wasremoved by distillation under reduced pressure to obtain salicylaldehyde2 (11.7 g). Paraformaldehyde (1.1 g) and morpholine (1.5 mL) weredissolved in acetonitrile (84 mL) and the prepared salicylaldehyde (3.0g) and triethylamine (2.8 mL) were put thereinto, followed by stirringat 80° C. for 12 hours. A saturated ammonium chloride aqueous solutionwas put thereinto to terminate the reaction, and the reactant wasextracted with dichloromethane three times. An organic layer wasseparated and dried over magnesium sulfate, followed by filtration anddistillation under reduced pressure to obtain salicylaldehyde 3containing morpholine (4.7 g). Prepared salicylaldehyde (4.7 g) and1,2-trans-diaminocyclohexane (1.0 mL) were dissolved in ethanol (84 mL),followed by stirring at room temperature for 3 hours. After distillationunder reduced pressure, the obtained reactant was recrystallized in amixed solvent of n-hexane and dichloromethane to obtain a symmetricalsalen derivative 4 (8.7 g). The prepared symmetrical salen derivative(1.5 g) was put into a round bottom flask wrapped with aluminum foil andwas dissolved into acetonitrile (47 mL) and then iodomethane (0.4 mL)was put thereinto, followed by stirring at room temperature for 1 day.After removing a solvent by distillation under reduced pressure, thereactant was dissolved in ethanol (80 mL) again and silver nitrate (883mg) was put thereinto, followed by stirring at 70° C. for 1.5 hours. Thereaction solution was filtered and distilled under reduced pressure toobtain a symmetrical salen ligand 5 containing ammonium salt (2.0 g).The prepared ligand (2.0 g) was dissolved in methanol (48 mL), andcobalt acetate tetrahydrate (673 mg) was put thereinto, followed bystirring at room temperature for 12 hours, and then lithium chloride(305 mg) was put thereinto and the reactant was oxidized by air. Theobtained metal complex was dissolved in dichloromethane again and anorganic layer was extracted with water to remove impurities. Afterdistillation under reduced pressure, a symmetrical cobalt-salen catalyst6 containing ammonium salt (1.3 g) was obtained. Result obtained byspectroscopy experiment of the symmetrical salen ligand containingammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 14.56 (2H, br s), 8.63 (2H, s), 7.59 (2H,s), 7.57 (2H, s), 4.63 (2H, d, J=13.0 Hz), 4.54 (2H, d, J=13.0 Hz),3.97-3.85 (8H, m), 3.63-3.29 (10H, m), 3.10 (6H, s), 1.95 (2H, br s),1.81 (2H, br s), 1.63 (2H, br s), 1.47 (2H, br s), 1.21 (18H, s)

[Preparation Example 2] Synthesis of Compound 10

A symmetrical cobalt-salen catalyst 10 containing ammonium salt preparedby the following method was prepared.

Paraformaldehyde (1.5 g) and N-ethylpiperazine (5.7 mL) were dissolvedin ethanol (75 mL) and salicylaldehyde 2 (8.0 g) prepared by the samemethod as Preparation Example 1 was put thereinto, followed by stirringat 80° C. for 3 days. A saturated ammonium chloride aqueous solution wasput thereinto to terminate the reaction, and the reactant was extractedwith dichloromethane three times. An organic layer was separated, driedover sodium sulfate and filtered, and then a solvent was removed bydistillation under reduced pressure and salicylaldehyde containingpiperazine 7 (10.4 g) was obtained by column chromatography. Theprepared salicylaldehyde derivative (6.1 g) was put into a round bottomflask wrapped with aluminum foil and was dissolved in acetonitrile (200mL) and then iodobutane (23 mL) was put thereinto, followed by stirringat 80° C. for 1 day. The solvent was removed by distillation underreduced pressure and the reactant was dissolved in ethanol (670 mL)again and silver nitrate (8.5 g) was put thereinto, followed by stirringat room temperature for 1 day. After the reaction solution was filtered,the solvent was removed by distillation under reduced pressure to obtaina salicylaldehyde derivative 8 containing ammonium salt (6.4 g). Theprepared salicylaldehyde derivative containing ammonium salt (4.9 g) and1,2-trans-diaminocyclohexane (0.6 mL) were dissolved into ethanol (45mL), followed by stirring at room temperature for 1 day. The solvent wasremoved by distillation under reduced pressure and a mixed solvent ofn-hexane and dichloromethane were put into the reactant again, followedby stirring at room temperature for 1 hour, and the reactant wasfiltered and dried to obtain a symmetrical salen derivative 9 (4.9 g).The prepared ligand (2.9 g) was dissolved in methanol (48 mL), andcobalt acetate tetrahydrate (697 mg) was put thereinto, followed bystirring at room temperature for 12 hours, and then lithium chloride(551 mg) was put thereinto and the reactant was oxidized by air. Theobtained metal complex was dissolved in dichloromethane again and anorganic layer was extracted with water to remove impurities. Afterdistillation under reduced pressure, a symmetrical cobalt-salen catalyst10 containing ammonium salt (1.9 g) was obtained. Result obtained byspectroscopy experiment of the salicylaldehyde derivative containingammonium salt was as follows.

¹H NMR (500 MHz, CDCl₃) δ 9.92 (1H, s), 7.54 (1H, s), 7.48 (1H, s), 3.73(2H, s), 3.69-3.63 (4H, m), 3.50-3.47 (2H, m), 2.91 (4H, s), 1.46-1.37(8H, m), 1.34-1.20 (8H, m), 1.27 (9H, s), 0.97-0.86 (6H, m)

[Preparation Example 3] Synthesis of Compound 15

A symmetrical cobalt-salen catalyst 15 containing ammonium salt preparedby the following method was prepared.

4-tert-butyl-salicylaldehyde 2 (7.1 g) was put into a mixture ofparaformaldehyde (3.6 g) and 1N hydrochloric acid aqueous solution (150mL), followed by stirring at room temperature for 2 days. A saturatedsodium bicarbonate aqueous solution was slowly put thereinto toneutralize the reactant, and the aqueous layer was extracted withdichloromethane. An organic layer was separated and dried over magnesiumsulfate, followed by filtration, and the solvent was removed bydistillation under reduced pressure to obtain chloromethylsalicylaldehyde 11 (7.0 g). After piperidine (2.9 g) was dissolved inacetonitrile (30 mL), the prepared chloromethyl salicylaldehyde (7.0 g)was put thereinto and stirred at room temperature for 3 hours. Asaturated sodium bicarbonate aqueous solution was put thereinto toterminate the reaction, and the reactant was extracted withdichloromethane. An organic layer was separated and dried over sodiumsulfate, followed by filtration, and a solvent was removed bydistillation under reduced pressure to obtain salicylaldehyde 12containing piperidine (8.0 g). The prepared salicylaldehyde derivative(8.0 g) was put into a round bottom flask wrapped with aluminum foil andwas dissolved in acetonitrile (24 mL) and then iodomethane (5.4 mL) wasput thereinto, followed by stirring at 40° C. for 1 day. After thesolvent was removed by distillation under reduced pressure, the reactantwas dissolved in ethanol (24 mL) again and silver nitrate (5.9 g) wasput thereinto, followed by stirring at 70° C. for 1.5 hours. After thereaction solution was filtered, the reactant was distilled under reducedpressure to obtain salicylaldehyde 13 containing ammonium salt (9.2 g).The prepared salicylaldehyde (9.2 g) and 1,2-trans-diaminocyclohexane(1.5 g) were dissolved in ethanol (45 mL), followed by reflux stirringfor 3 hours. After distillation under reduced pressure, the obtainedreactant was recrystallized in a mixed solvent of n-hexane anddichloromethane to obtain a symmetrical salen ligand 14 (19.5 g). Theprepared ligand (19.5 g) was dissolved in methanol (200 mL), and cobaltacetate tetrahydrate (6.8 g) was put thereinto, followed by stirring atroom temperature for 12 hours, and then lithium chloride (1.3 g) was putthereinto and the reactant was oxidized by air. The obtained metalcomplex was dissolved in dichloromethane again and an organic layer wasextracted with water to remove impurities. After distillation underreduced pressure, a symmetrical cobalt-salen catalyst 15 containingammonium salt (13.1 g) was obtained. Result obtained by spectroscopyexperiment of the symmetrical salen ligand containing ammonium salt wasas follows.

¹H NMR (500 MHz, CDCl₃) δ 13.93 (2H, br s), 8.36 (2H, s), 7.58 (2H, s),7.26 (2H, s), 4.24-4.21 (4H, m), 3.69-3.50 (6H, m), 3.41 (6H, s),2.79-2.68 (4H, m), 2.04-1.21 (38H, m)

[Preparation Example 4] Synthesis of Compound 19

A symmetrical cobalt-salen catalyst 19 containing ammonium salt preparedby the following method was prepared.

After dibutylamine (6.2 mL) was dissolved in acetonitrile (30 mL), thechloromethyl salicylaldehyde 11 (7.0 g) prepared by the same method asPreparation Example 3 was put thereinto and stirred at room temperaturefor 3 hours. A saturated sodium bicarbonate aqueous solution was putthereinto to terminate the reaction, and the reactant was extracted withdichloromethane. An organic layer was separated and dried over magnesiumsulfate, followed by filtration and distillation under reduced pressureto obtain salicylaldehyde 16 containing dibutylamine (9.3 g). Theprepared salicylaldehyde derivative (9.3 g) was put into a round bottomflask wrapped with aluminum foil and was dissolved in acetonitrile (24mL) and then iodomethane (5.4 mL) was put thereinto, followed bystirring at 40° C. for 1 day. After the solvent was removed bydistillation under reduced pressure, the reactant was dissolved inethanol (24 mL) again and silver nitrate (5.9 g) was put thereinto,followed by stirring at 70° C. for 1.5 hours. After the reactionsolution was filtered, the reactant was distilled under reduced pressureto obtain salicylaldehyde 17 containing ammonium salt (9.7 g). Theprepared salicylaldehyde (9.7 g) and 1,2-trans-diaminocyclohexane (1.4g) were dissolved in ethanol (45 mL), followed by reflux stirring for 3hours. After distillation under reduced pressure, the obtained reactantwas recrystallized in a mixed solvent of n-hexane and dichloromethane toobtain a symmetrical salen ligand 18 (19.6 g). The prepared ligand (19.6g) was dissolved in methanol (200 mL), and cobalt acetate tetrahydrate(6.2 g) was put thereinto, followed by stirring at room temperature for12 hours, and then lithium chloride (1.1 g) was put thereinto and thereactant was oxidized by air. The obtained metal complex was dissolvedin dichloromethane again and an organic layer was extracted with waterto remove impurities. After distillation under reduced pressure, asymmetrical cobalt-salen catalyst 19 containing ammonium salt (12.3 g)was obtained. Result obtained by spectroscopy experiment of thesymmetrical salen ligand containing ammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 8.58 (2H, s), 7.51 (2H, s), 7.43 (2H, s),4.46 (4H, ABq, J=11.5, 6.5 Hz), 3.23 (2H, br s), 2.97 (6H, s), 2.88-2.51(8H, m), 2.05-1.04 (42H, m), 0.97-0.78 (12H, m)

[Preparation Example 5] Synthesis of Compound 22

A symmetrical cobalt-salen catalyst 22 containing ammonium salt preparedby the following method was prepared.

After the salicylaldehyde derivative 16 (9.3 g) prepared by the samemethod as Preparation Example 4 was dissolved in acetonitrile (30 mL),dimethyl sulfate (2.8 mL) was put thereinto, followed by stirring atroom temperature for 1 day. A solvent was removed by distillation underreduced pressure to obtain salicylaldehyde 20 (11.5 g) containingammonium salt. The prepared salicylaldehyde (11.5 g) and1,2-trans-diaminocyclohexane (1.5 g) were dissolved in ethanol (45 mL),followed by reflux stirring for 3 hours. After distillation underreduced pressure, the obtained reactant was recrystallized in a mixedsolvent of n-hexane and dichloromethane to obtain a symmetrical salenligand 21 (20.3 g). The prepared ligand (20.3 g) was dissolved intomethanol (200 mL), and cobalt acetate tetrahydrate (6.6 g) was putthereinto, followed by stirring at room temperature for 12 hours, andthen lithium chloride (1.2 g) was put thereinto and the reactant wasoxidized by air. The obtained metal complex was dissolved indichloromethane again and an organic layer was extracted with water toremove impurities. After distillation under reduced pressure, asymmetrical cobalt-salen catalyst 22 containing ammonium salt (16.0 g)was obtained. Result obtained by spectroscopy experiment of thesymmetrical salen ligand containing ammonium salt was as follows.

¹H NMR (500 MHz, CDCl₃) δ 8.39 (2H, s), 7.57 (2H, s), 7.30 (2H, s), 4.30(4H, q, J=7.0 Hz), 3.77 (6H, s), 3.59 (2H, br s), 3.19-2.82 (8H, m),2.01-1.21 (42H, m), 0.96-0.92 (12H, m)

[Preparation Example 6] Synthesis of Compound 26

A symmetrical cobalt-salen catalyst 26 containing ammonium salt preparedby the following method was prepared.

After dibutyl[2-(methylamino)ethyl]amine (6.8 g) was dissolved inacetonitrile (30 mL), the chloromethyl salicylaldehyde 11 (7.0 g)prepared by the same method as Preparation Example 3 was put thereintoand stirred at room temperature for 3 hours. A saturated sodiumbicarbonate aqueous solution was put thereinto to terminate thereaction, and the reactant was extracted with dichloromethane. Anorganic layer was separated and dried over sodium sulfate, followed byfiltration and distillation under reduced pressure to obtainsalicylaldehyde 23 containing dibutyl[2-(methylamino)ethyl]amine (9.5g). The prepared salicylaldehyde derivative (9.5 g) was put into a roundbottom flask wrapped with aluminum foil and was dissolved inacetonitrile (30 mL) and then iodomethane (9.4 mL) was put thereinto,followed by stirring at 40° C. for 1 day. After the solvent was removedby distillation under reduced pressure, the reactant was dissolved inethanol (30 mL) again and silver nitrate (10.2 g) was put thereinto,followed by stirring at 70° C. for 1.5 hours. After the reactionsolution was filtered, the reactant was distilled under reduced pressureto obtain salicylaldehyde 24 containing ammonium salt (11.7 g). Theprepared salicylaldehyde (11.7 g) and 1,2-trans-diaminocyclohexane (1.3g) were dissolved in ethanol (45 mL), followed by reflux stirring for 3hours. After distillation under reduced pressure, the obtained reactantwas recrystallized in a mixed solvent of n-hexane and dichloromethane toobtain a symmetrical salen ligand 25 (21.9 g). The prepared ligand (21.9g) was dissolved in methanol (200 mL), and cobalt acetate tetrahydrate(5.3 g) was put thereinto, followed by stirring at room temperature for12 hours, and then lithium chloride (1.0 g) was put thereinto and thereactant was oxidized by air. The obtained metal complex was dissolvedin dichloromethane again and an organic layer was extracted with waterto remove impurities. After distillation under reduced pressure, asymmetrical cobalt-salen catalyst 26 containing ammonium salt (15.4 g)was obtained. Result obtained by spectroscopy experiment of thesymmetrical cobalt-salen containing ammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 8.06 (2H, s), 7.58 (2H, s), 7.51 (2H, s),5.01 (2H, d, J=11.5 Hz), 4.90 (2H, d, J=11.5 Hz), 3.73 (4H, q, J=7.0Hz), 3.58 (2H, br s), 3.51 (2H, s), 3.33 (12H, s), 3.26 (2H, s),3.06-2.99 (8H, m), 1.98-1.56 (14H, m), 1.85 (6H, s), 1.28 (18H, s),1.26-1.19 (10H, m), 0.98-0.86 (12H, m)

[Preparation Example 7] Synthesis of Compound 31

A symmetrical cobalt-salen catalyst 31 containing ammonium salt preparedby the following method was prepared.

N,N′-dimethylhexane-1,6-diamine (2.6 g) was put into a mixture ofpotassium carbonate (5.5 g), paraformaldehyde (2.2 g) and ethanol (20mL) and the mixture was stirred at room temperature for 3 days. A solidwas removed by filtration and the reactant was distilled under reducedpressure to obtain a hexyldiamine derivative 27 substituted withethoxymethyl group (4.2 g). The prepared hexyldiamine derivative (4.2 g)was dissolved in acetonitrile (40 mL) and 4-tert-butyl-salicylaldehyde 2(5.8 g) prepared by the same method as Preparation Example 1 was putthereinto, followed by reflux stirring for 1 day, to obtain symmetricalsalicylaldehyde 28 (6.1 g). After dimethyl sulfate (1.1 mL) wasdissolved in acetonitrile (20 mL), the prepared symmetricalsalicylaldehyde (6.1 g) was put thereinto and stirred at roomtemperature for 1 day. A solvent was removed by distillation underreduced pressure and a symmetrical salicylaldehyde 29 (6.6 g) wasobtained. Result obtained by spectroscopy experiment of thesalicylaldehyde linked with N,N′-dimethylhexane-1,6-diamine was asfollows.

¹H NMR (500 MHz, CDCl₃) δ 11.20 (2H, br s), 10.38 (2H, s), 7.64 (2H, s),7.38 (2H, s), 3.74 (4H, s), 2.51-2.50 (4H, m), 2.31 (6H, s), 1.59 (4H,br s), 1.37-1.30 (4H, m), 1.28 (18H, s)

The prepared symmetrical salicylaldehyde derivative (6.6 g) and1,2-trans-diaminocyclohexane (1.2 g) were dissolved in ethanol (35 mL),followed by reflux stirring for 3 hours. After distillation underreduced pressure, the obtained reactant was recrystallized in a mixedsolvent of n-hexane and dichloromethane to obtain a symmetrical salenligand 30 (6.6 g). The prepared ligand (6.6 g) was dissolved in methanol(200 mL), and cobalt acetate tetrahydrate (2.5 g) was put thereinto,followed by stirring at room temperature for 12 hours, and then lithiumchloride (460 mg) was put thereinto and the reactant was oxidized byair. The obtained metal complex was dissolved in dichloromethane againand an organic layer was extracted with water to remove impurities.After distillation under reduced pressure, a symmetrical cobalt-salencatalyst 31 containing an ammonium salt (5.7 g) was obtained. Resultobtained by spectroscopy experiment of the symmetrical salen ligandcontaining ammonium salt was as follows.

¹H NMR (500 MHz, CDCl₃) δ 13.47 (2H, br s), 8.27-8.25 (2H, m), 7.32-6.81(4H, m), 3.73 (4H, q, J=6.5 Hz), 2.89-2.80 (2H, m), 2.44-2.43 (4H, m),2.41 (6H, s), 2.22 (6H, s), 1.87-0.97 (34H, m)

[Preparation Example 8] Synthesis of Compounds 35 and 36

Symmetrical cobalt-salen catalysts 35 and 36 containing ammonium saltprepared by the following method were prepared.

Salicylaldehyde 2 (3.1 g) prepared by the same method as PreparationExample 1, paraformaldehyde (0.8 g), 48% aqueous hydrogen bromidesolution (15 mL), a catalytic amount of concentrated sulfuric acid wasmixed together and stirred at 70° C. for 20 hours. After the reactantwas cooled at room temperature, dichloromethane was put thereinto andextracted with water, the solvent was removed by distillation underreduced pressure, and bromomethyl salicylaldehyde 32 (4.4 g) wasobtained. The prepared salicylaldehyde (1.5 g) was dissolved in toluene(20 mL), followed by stirring and triethylamine (1.5 g) was slowly putthereinto, followed by stirring at room temperature for 12 hours. Theobtained solid was filtered and washed with toluene and n-hexane,respectively and then dried in vacuo to obtain salicylaldehyde 33 (1.7g) containing ammonium salt was obtained. The obtained salicylaldehyde(1.4 g) was dissolved in ethanol (20 mL) and1,2-trans-diaminocyclohexane (220 mg) was put thereinto, followed byreflux stirring for 5 hours. After cooling to room temperature, silvernitrate (420 mg) was put thereinto, followed by stirring at roomtemperature for 15 hours. After the obtained solid was filtered andremoved, the solution was distilled under reduced pressure to remove asolvent to obtain a ligand 34 containing ammonium salt (1.3 g). Theprepared ligand (1.0 g) was dissolved in methanol (50 mL), and cobaltacetate (240 mg) was put thereinto, followed by stirring at roomtemperature for 18 hours, and then lithium chloride (240 mg) was putthereinto and the reactant was oxidized by air. The obtained metalcomplex was dissolved into dichloromethane again and an organic layerwas extracted with water to remove impurities. After distillation underreduced pressure, a symmetrical cobalt-salen catalyst 35 containing anammonium salt (0.7 g) was obtained. The catalyst containing chlorine(0.7 g) was dissolved in dichloromethane (55 mL) again and silveracetate (240 mg) was put thereinto, followed by stirring for 3 hours,and the obtained solid was filtered and removed. After a solvent wasremoved by distillation under reduced pressure, a symmetricalcobalt-salen catalyst 36 containing acetate (0.7 g) was obtained. Resultobtained by spectroscopy experiment of the symmetrical salen ligandcontaining ammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 13.54 (2H, s), 8.51 (2H, s), 7.32 (2H, s),7.25 (2H, s), 4.38 (4H, s), 3.06-3.04 (12H, m), 1.85-1.11 (28H, m),0.90-0.88 (18H, m)

[Preparation Example 9] Synthesis of Compound 40

A symmetrical cobalt-salen catalyst 40 containing ammonium salt preparedby the following method was prepared.

Bromomethyl salicylaldehyde 32 (1.5 g) prepared by the same method asPreparation Example 8 was dissolved in dichloromethane (3 mL) andtriethylamine (1.1 g) and N,N′-diethylethylenediamine (0.3 g) wassequentially and slowly put thereinto. The reactant was stirred at roomtemperature for 20 hours, and extracted with water. The reactant wasdried over magnesium sulfate, followed by filtration, and a solvent wasremoved by distillation under reduced pressure to obtaindisalicylaldehyde 37 (0.7 g). Result obtained by spectroscopy experimentof the salicylaldehyde derivative was as follows.

¹H NMR (500 MHz, CDCl₃) δ 11.32 (2H, br s), 9.89 (2H, s). 7.64 (2H, d,J=2.4 Hz), 7.53 (2H, d, J=2.5 Hz). 3.67 (4H, s), 2.66-2.56 (8H, m),1.20-0.98 (24H, m)

The prepared disalicylaldehyde (0.7 g) and 1,2-trans-diaminocyclohexane(0.3 g) were dissolved in ethanol (12 mL), followed by reflux stirringfor 5 hours. A solvent was removed by distillation under reducedpressure, and a symmetrical salen derivative 38 (960 mg) was obtained.The prepared symmetrical salen derivative (960 mg) was put into a roundbottom flask wrapped with aluminum foil and was dissolved inacetonitrile (25 mL) and then iodomethane (2.5 mL) was put thereinto,followed by stirring at room temperature for 18 hours. After the solventwas removed by distillation under reduced pressure, the reactant wasdissolved in ethanol (22 mL) and silver nitrate (407 mg) was putthereinto, followed by stirring at room temperature for 15 hours. Thereaction solution was filtered and distilled under reduced pressure toobtain a symmetrical salen ligand 39 containing ammonium salt (1.1 g).The prepared ligand (1.0 g) was put into a round-bottom flask wrappedwith aluminum foil and dissolved into dichloromethane (25 mL) under anitrogen atmosphere, and cobalt acetate (220 mg) was put thereinto,followed by stirring at room temperature for 5 hours. After the reactantwas exposed to air, silver acetate (210 mg) was put thereinto, followedby stirring at room temperature for 4 hours, a solid was removed byfiltration and a solvent was removed by distillation under reducedpressure, thereby obtaining a symmetrical cobalt-salen catalyst 40 (1.0g) containing ammonium salt. Result obtained by spectroscopy experimentof the symmetrical salen ligand containing ammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 13.64 (2H, s), 8.48 (2H, s), 7.23 (2H, s),7.13 (2H, s), 3.53 (6H, s), 3.37 (4H, s), 2.43-2.32 (8H, m), 1.86-1.23(10H, m), 1.20-0.98 (24H, m)

[Preparation Example 10] Synthesis of Compound 47

A symmetrical cobalt-salen catalyst 47 containing ammonium salt preparedby the following method was prepared.

2-methylphenol (10.1 g) was dissolved in toluene (300 mL) andparaformaldehyde (20.3 g), magnesium chloride (17.7 g) and triethylamine(49.9 mL) were put thereinto, followed by reflux stirring at 130° C. for5 hours. After the reactant was cooled at room temperature, 2Nhydrochloric acid aqueous solution (100 mL) was put thereinto, followedby stirring 1 hour. After layer separation, the aqueous solution layerwas extracted with ethyl acetate once and the combined organic layer wasextracted with water and a saturated sodium bicarbonate aqueoussolution, respectively. Magnesium sulfate was put into the organiclayer, followed by stirring and filtration, and the solvent was removedby distillation under reduced pressure, and then the salicylaldehyde 42(13.0 g) was obtained. The prepared salicylaldehyde (4.5 g),paraformaldehyde (1.3 g), 12 N hydrochloric acid aqueous solution (70mL) was mixed and stirred at room temperature for 12 hours. After theobtained solid was filtered and dissolved in diethylether (50 mL) againand then extracted with water and a saturated sodium bicarbonate aqueoussolution, respectively. Magnesium sulfate was put into the organiclayer, followed by stirring and filtration, and the solvent was removedby distillation under reduced pressure, and then the salicylaldehyde 43(3.6 g) containing chloromethyl was obtained. The prepared chloromethylsalicylaldehyde (1.0 g) was dissolved in toluene (20 mL), followed bystirring and tributylamine (1.5 g) was slowly put thereinto, followed bystirring at room temperature for 12 hours. The resulting solid wasfiltered and washed with toluene and n-hexane, respectively and thendried in vacuo to obtain the salicylaldehyde 44 (1.84 g) containingammonium salt was obtained. Result obtained by spectroscopy experimentof the salicylaldehyde derivative was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 10.96 (1H, br s), 10.05 (1H, s), 7.54 (1H,s), 7.43 (1H, s), 4.38 (2H, s), 2.99-2.95 (6H, m), 2.19 (3H, s),1.66-1.60 (6H, m), 1.34-1.28 (6H, m), 0.89 (9H, t, J=5.6 Hz)

The obtained salicylaldehyde (1.5 g) was dissolved in ethanol (20 mL)and 1,2-trans-diaminocyclohexane (0.2 g) was put thereinto, followed byreflux stirring for 5 hours. After cooling to room temperature, silvernitrate (0.45 g) was put thereinto, followed by stirring at roomtemperature for 15 hours. After the obtained solid was filtered andremoved, the solution was distilled under reduced pressure to remove asolvent to obtain a ligand 45 containing ammonium salt (1.46 g). Theprepared ligand (993 mg) was dissolved in methanol (50 mL), and cobaltacetate (240 mg) was put thereinto, followed by stirring at roomtemperature for 18 hours, and then lithium chloride (240 mg) was putthereinto and the reactant was oxidized by air. The obtained metalcomplex was dissolved in dichloromethane again and an organic layer wasextracted with water to remove impurities. After distillation underreduced pressure, a symmetrical cobalt-salen catalyst 46 containingammonium salt (870 mg) was obtained. The catalyst containing chlorine(870 mg) was dissolved in dichloromethane (50 mL) again and silveracetate (220 mg) was put thereinto, followed by stirring for 3 hours,and the obtained solid was filtered and removed. After a solvent wasremoved by distillation under reduced pressure, a symmetricalcobalt-salen catalyst 47 containing acetate (770 mg) was obtained.Result obtained by spectroscopy experiment of the symmetrical salenligand containing ammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 13.60 (2H, s), 8.47 (2H, s), 7.10 (4H, s),4.26 (4H, s), 2.80 (12H, s), 2.10 (6H, s), 1.86-1.79 (6H, m), 1.56-1.53(12H, m), 1.51-1.38 (4H, m), 1.31-1.27 (12H, m), 0.89 (18H, t, J=5.6 Hz)

[Preparation Example 11] Synthesis of Compound 52

A symmetrical cobalt-salen catalyst 52 containing ammonium salt preparedby the following method was prepared.

Chloromethyl salicylaldehyde 43 (1.2 g) prepared by the same method asPreparation Example 10 was dissolved in acetonitrile (30 mL), followedby stirring and triethylamine (1.2 mL) and morpholine (1.2 g) wereslowly put thereinto, followed by stirring at room temperature 20 hours.After the reaction was completed by adding water thereto, the aqueoussolution layer was extracted with ethyl acetate, an organic layer wasdried over magnesium sulfate, followed by filtration and distillationunder reduced pressure to remove a solvent, thereby obtainingsalicylaldehyde 48 (1.4 g) containing morpholine. The preparedsalicylaldehyde (1.4 g) was dissolved in ethanol (30 mL), and then1,2-trans-diaminocyclohexane (0.3 g) was put thereinto, followed byreflux stirring for 5 hours. After the reactant was cooled at roomtemperature and distilled under reduced pressure to remove a solvent, asalen derivative 49 (1.4 g) was obtained. The prepared salen derivative(1.1 g) was put into a round bottom flask wrapped with aluminum foil andwas dissolved in acetonitrile (30 mL) and then iodomethane (0.3 mL) wasput thereinto, followed by stirring at room temperature for 18 hours.After the solvent was removed by distillation under reduced pressure,the reactant was dissolved in ethanol (28 mL) again and silver nitrate(503 mg) was put thereinto, followed by stirring at room temperature for15 hours. After the obtained solid was filtered and removed, thesolution was distilled under reduced pressure to remove a solvent,thereby obtaining a ligand 50 containing ammonium salt (1.24 g). Theprepared ligand (0.8 g) was dissolved in methanol (50 mL), and cobaltacetate (240 mg) was put thereinto, followed by stirring at roomtemperature for 18 hours, and then lithium chloride (240 mg) was putthereinto and the reactant was oxidized by air. The obtained metalcomplex was dissolved in dichloromethane again and an organic layer wasextracted with water to remove impurities. After distillation underreduced pressure, a symmetrical cobalt-salen catalyst 51 containingammonium salt (680 mg) was obtained. The catalyst containing chlorine(679 mg) was dissolved into dichloromethane (50 mL) again and silveracetate (220 mg) was put thereinto, followed by stirring for 3 hours,and the obtained solid was filtered and removed. After a solvent wasremoved by distillation under reduced pressure, a symmetricalcobalt-salen catalyst 52 containing acetate (679 mg) was obtained.Result obtained by spectroscopy experiment of the symmetrical salenligand containing ammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 14.18 (2H, s), 8.59 (2H, s), 7.41 (2H, s),7.37 (2H, s), 4.56 (4H, s), 3.93-3.92 (8H, m), 3.37-3.32 (14H, m), 2.12(6H, s), 1.93-1.47 (10H, m)

[Preparation Example 12] Synthesis of Compound 57

A symmetrical cobalt-salen catalyst 57 containing ammonium salt preparedby the following method was prepared.

3-morpholin propylene amine (2.5 g) was dissolved in dichloromethane (40mL) and triethylamine (3.6 mL) was put thereinto and the reactant wascooled at −20° C. Methyl chloroformate (2.0 mL) was slowly put thereintoand a temperature was slowly raised to room temperature. After thereactant was stirred for 3 hours, 0.1 N hydrochloric acid aqueoussolution was put thereinto and an organic layer was separated andextracted with water and a saturated sodium bicarbonate aqueoussolution, respectively. The reactant was dried over magnesium sulfate,filtered, and distilled under reduced pressure to remove a solvent. Amixture of lithium aluminum hydride (1.9 g) and tetrahydrofuran (18 mL)was cooled at 0° C. under a nitrogent atmosphere, and a mixture of theprepared carbamate (3.4 g) and tetrahydrofuran (18 mL) was slowly putthereinto. A temperature was raised and the reactant was reflux stirredfor 4 hours and cooled at 0° C. and diluted with diethyl ether (12 mL).The reactant was strongly stirred and then water (1.6 mL), 15% sodiumhydroxide aqueous solution (1.6 mL), water (4.8 mL) were sequentiallyand slowly put thereinto, followed by stirring for 5 hours. The obtainedsolid was filtered and removed, followed by distillation under reducedpressure, to thereby obtain a methylamine derivative 53 (2.6 g). Resultobtained by spectroscopy experiment of the methylamine derivative was asfollows.

¹H NMR (500 MHz, CDCl₃) δ 3.72 (4H, t, J=4.0 Hz), 2.63-2.57 (2H, m),2.42-2.37 (9H, m), 1.72-1.64 (3H, m)

Chloromethyl salicylaldehyde 43 (1.2 g) prepared by the same method asPreparation Example 10 was dissolved in acetonitrile (30 mL), followedby stirring and triethylamine (1.2 mL) and the prepared methylamine (2.3g) were slowly put thereinto, followed by stirring at room temperature20 hours. After the reaction was completed by adding water thereto, theaqueous solution layer was extracted with ethyl acetate, an organiclayer was dried over magnesium sulfate, followed by filtration anddistillation under reduced pressure to remove a solvent, therebyobtaining salicylaldehyde 54 (1.5 g) containing amine. The preparedsalicylaldehyde (1.2 g) was dissolved in ethanol (20 mL) and1,2-trans-diaminocyclohexane (217 mg) was put thereinto, followed byreflux stirring for 5 hours. After the reactant was cooled at roomtemperature and distilled under reduced pressure to remove a solvent, asalen derivative 55 (1.1 g) was obtained. The prepared salen derivative(1.4 g) was put into a round bottom flask wrapped with aluminum foil andwas dissolved in acetonitrile (30 mL) and then iodomethane (0.3 mL) wasput thereinto, followed by stirring at room temperature for 18 hours.After the solvent was removed by distillation under reduced pressure,the reactant was dissolved in ethanol (26 mL) again and silver nitrate(483 mg) was put thereinto, followed by stirring at room temperature for15 hours. After the obtained solid was filtered and removed, thesolution was distilled under reduced pressure to remove a solvent,thereby obtaining a ligand 56 containing ammonium salt (1.87 g). Theprepared ligand (1.1 g) was put into a round-bottom flask wrapped withaluminum foil and dissolved in dichloromethane (25 mL) under a nitrogenatmosphere, and cobalt acetate (182 mg) was put thereinto, followed bystirring at room temperature for 5 hours. After the reactant was exposedto air, silver acetate (182 mg) was put thereinto, followed by stirringat room temperature for 4 hours, a solid was removed by filtration and asolvent was removed by distillation under reduced pressure, therebyobtaining a symmetrical cobalt-salen catalyst 57 (1.0 g) containingammonium salt. Result obtained by spectroscopy experiment of thesymmetrical salen ligand containing ammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 14.20 (2H, s), 8.63 (2H, s), 7.42 (4H, d,J=18.0 Hz), 4.51 (4H, s), 3.95 (8H, s), 3.51-3.48 (14H, m), 3.21-3.19(8H, m), 3.00-2.89 (12H, m), 2.34-2.19 (4H, m), 2.16 (6H, s), 1.88-1.48(10H, m)

[Preparation Example 13] Synthesis of Compound 60

A symmetrical cobalt-salen catalyst 60 containing ammonium salt preparedby the following method was prepared.

Chloromethyl salicylaldehyde 43 (1.2 g) prepared by the same method asPreparation Example 10 was dissolved in toluene (40 mL), followed bystirring and triethylamine (2.4 g) was slowly put thereinto, followed bystirring at room temperature 12 hours. The resulting solid was filteredand washed with toluene and n-hexane, respectively and then dried invacuo to obtain salicylaldehyde 58 (2.8 g) containing ammonium salt wasobtained. Result obtained by spectroscopy experiment of thesalicylaldehyde derivative was as follows.

¹H NMR (500 MHz, CDCl₃) δ 11.35 (1H, s), 9.95 (1H, s), 7.53 (1H, s),7.42 (1H, s), 5.02 (2H, s), 3.77-3.12 (6H, m), 2.23 (3H, s), 1.49-1.44(9H, m)

The obtained salicylaldehyde (1.1 g) was dissolved in ethanol (20 mL)and 1,2-trans-diaminocyclohexane (217 mg) was put thereinto, followed byreflux stirring for 5 hours. After the reactant was cooled at roomtemperature and distilled under reduced pressure to remove a solvent, asalen derivative 59 (1.1 g) was obtained. The prepared ligand (741 mg)was dissolved in methanol (50 mL) and cobalt acetate (240 mg) was putthereinto, followed by stirring at room temperature for 18 hours, andlithium chloride (240 mg) was put thereinto and the reactant wasoxidized by air. The resulting metal complex was dissolved indichloromethane again and an organic layer was extracted with water toremove impurities. After distillation under reduced pressure, asymmetrical cobalt-salen catalyst 60 containing ammonium salt (592 mg)was obtained. Result obtained by spectroscopy experiment of thesymmetrical salen ligand containing ammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 13.20 (2H, s), 8.57 (2H, s), 7.22 (4H, s),4.35 (4H, s), 2.96-2.64 (12H, m), 2.22 (6H, s), 1.90-1.45 (10H, m), 0.98(18H, t, J=5.6 Hz)

[Preparation Example 14] Synthesis of Compound 65

A symmetrical cobalt-salen catalyst 65 containing ammonium salt preparedby the following method was prepared.

Salicylaldehyde (11.5 g) was dissolved in ethanol (100 mL),paraformaldehyde (6.2 g) and morpholine (18.0 g) were put thereinto,followed by stirring at 80° C. for 24 hours. A solvent was removed bydistillation under reduced pressure and the reactant was dissolved indichloromethane again and extracted with water and saturated sodiumchloride aqueous solution. An organic layer was dried over magnesiumsulfate, followed by filtration, and a solvent was removed bydistillation under reduced pressure to obtain a salicylaldehydederivative 62 (27.4 g). The prepared salicylaldehyde derivative (1.2 g)was dissolved in ethanol (20 mL) and 1,2-trans-diaminocyclohexane (217mg) was put thereinto, followed by reflux stirring for 5 hours. Afterthe reactant was cooled at room temperature and distilled under reducedpressure to remove a solvent, salen 63 (1.1 g) containing amine wasobtained. Result obtained by spectroscopy experiment of the salen was asfollows.

¹H NMR (500 MHz, DMSO-d₆) δ 13.64 (2H, s), 8.48 (2H, s), 7.23 (2H, s),7.13 (2H, s), 3.54-3.52 (16H, m), 3.39-3.36 (8H, m), 2.36 (4H, s),2.34-2.31 (8H, m), 2.25 (4H, s), 1.88-1.09 (10H, m)

The prepared salen (0.6 g) was completely dissolved in acetonitrile (50mL) and then allyl bromide (2.0 g) was slowly put thereinto. Thereactant was stirred at room temperature for 18 hours and a solvent wasremoved by distillation under reduced pressure, a ligand 64 (1.0 g) wasobtained. After the prepared ligand (1.0 mg) was put into a round-bottomflask wrapped with aluminum foil and dissolved in dichloromethane (20mL) under a nitrogen atmosphere, cobalt acetate (142 mg) was putthereinto, and the reactant was exposed in the air, followed by stirringat room temperature for 5 hours. After a solvent was removed bydistillation under reduced pressure, a symmetrical cobalt-salen catalyst65 containing ammonium salt (0.9 g) was obtained. Result obtained byspectroscopy experiment of the symmetrical salen ligand containingammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 13.94 (2H, s), 8.48 (2H, s), 7.25 (2H, s),7.15 (2H, s), 4.59-4.56 (4H, m), 3.92-3.87 (8H, m), 3.52-3.43 (24H, m),3.07 (8H, s), 2.36 (8H, s), 2.24 (8H, s), 1.92-1.32 (10H, m)

[Preparation Example 15] Synthesis of Compound 68

A symmetrical cobalt-salen catalyst 68 containing ammonium salt preparedby the following method was prepared.

Bromomethyl salicylaldehyde 32 (1.0 g) prepared by the same method asPreparation Example 8 was dissolved in toluene (13 mL) and 4-tert-butylpyridine (0.6 mL) was slowly put thereinto. The reactant was stirred atroom temperature for 18 hours, diethyl ether (3 mL) was put thereinto,followed by additional stirring for 30 minutes. The obtained solid wasfiltered and washed with diethyl ether (10 mL) and then dried in vacuo.The reactant was dissolved in dichloromethane (11 mL) and silver nitrate(0.6 g) was put thereinto, followed by stirring at room temperature for1 hour. The obtained solid was filtered and removed, followed bydistillation under reduced pressure to obtain salicylaldehyde 66containing ammonium salt (1.2 g). The obtained salicylaldehyde (1.2 g)was dissolved in ethanol (17 mL), and 1,2-trans-diaminocyclohexane (0.2mL) was put thereinto, followed by stirring at room temperature for 12hours. The reactant was distilled under reduced pressure to obtain aligand 67 (1.3 g) containing ammonium salt. The prepared ligand (300 mg)was put into a round-bottom flask wrapped with aluminum foil anddissolved into dichloromethane (2 mL) under a nitrogen atmosphere, andcobalt acetate (62 mg) was put thereinto, followed by stirring at roomtemperature for 5 hours. After the reactant was exposed to air, silveracetate (68 mg) was put thereinto, followed by stirring at roomtemperature for 4 hours, a solid was removed by filtration and a solventwas removed by distillation under reduced pressure, thereby obtaining asymmetrical cobalt-salen catalyst 68 (341 mg) containing ammonium salt.Result obtained by spectroscopy experiment of the symmetrical salenligand containing ammonium salt was as follows.

¹H NMR (500 MHz, DMSO-d₆) δ 14.12 (2H, s), 8.98 (4H, d, J=7.0 Hz), 8.54(2H, s), 8.46 (4H, d, J=7.0 Hz), 7.76 (2H, d, J=2.5 Hz), 7.40 (2H, d,J=2.5 Hz), 5.66 (4H, ABq, J=36.0, 13.5 Hz), 3.50 (2H, m), 1.87 (2H, m),1.78 (2H, m), 1.58 (2H, m), 1.44 (2H, m), 1.32 (18H, s), 1.22 (18H, s)

Examples 1 to 5

Propylene oxide (PO) and each catalyst were put into a high pressurestainless steel reactor at each molar ratio as shown in the followingTable 1 and the reactor was completely fastened. Carbon dioxide (CO₂)having ultra-high purity was slowly filled into the high pressurereactor and reaction was performed under predetermined pressure,operating temperature and time as shown in the following Table 1. Afterthe reaction was completed, the reaction was cooled and remaining carbondioxide was slowly discharged. After the catalyst was removed, thereactant was dried in vacuo to obtain poly(propylene carbonate).Physical properties of the obtained poly(propylene carbonate) were shownin the following Table 2.

TABLE 1 Ex- CO₂ Reaction Reaction am- PO:Catalyst Pressure TemperatureTime ple Catalyst (Molar Ratio) (bar) (° C.) (hr) 1 Preparation 2,000:130 28 48 Example 3 2 Preparation 2,000:1 30 28 48 Example 5 3Preparation 2,000:1 30 28 48 Example 6 4 Preparation 2,000:1 30 28 48Example 11 5 Preparation 2,000:1 25 28 48 Example 15

TABLE 2 PO Conversion Example Ratio Selectivity M_(n) PDI TON 1 82% 99%7,600 1.22 1,624 2 63% 99% 7,400 1.21 1,247 3 63% 99% 4,100 1.26 1,247 448% 99% — — 950 5 13% 80% — — 208

Examples 6 to 9

Propylene oxide (PO), each catalyst and adipic acid were put into a highpressure stainless steel reactor at each molar ratio as shown in thefollowing Table 3 and the reactor was completely fastened. A solvent wasput thereinto as needed. Carbon dioxide (CO₂) having ultra-high puritywas slowly filled into the high pressure reactor and reaction wasperformed under predetermined pressure, operating temperature and timeas shown in the following Table 3. After the reaction was completed, thereaction was cooled and remaining carbon dioxide was slowly discharged.After the catalyst was removed, the reactant was dried in vacuo toobtain poly(propylene carbonate) and physical properties of the obtainedpoly(propylene carbonate) were shown in the following Table 4.

TABLE 3 PO:Catalyst: CO₂ Reaction Reaction PO:Solvent Adipic AcidPressure Temperature Time (v/v) Example Catalyst (Molar Ratio) (bar) (°C.) (hr) Solvent (Volume Ratio) 6 Preparation 10,000:1:500  30 40 53Toluene 2:1 Example 1 7 Preparation 10,000:1:500  30 40 48 Toluene 2:1Example 2 8 Preparation 2,000:1:100 30 28 48 — — Example 3 9 Preparation2,000:1:10  30 28 48 Toluene 2:1 Example 4 10 Preparation 2,000:1:10  3028 48 — — Example 5 11 Preparation 2,000:1:10  30 28 48 — — Example 6 12Preparation 10,000:1:450  30 50 44 Toluene 2:1 Example 7 13 Preparation2,000:1:10  30 25 48 1,2- 2:1 Example 8 dichloroethane 14 Preparation2,000:1:100 30 50 48 1,2- 3:2 Example 8 dichloroethane 15 Preparation2,000:1:100 30 50 66 Toluene 2:1 Example 9 16 Preparation 2,000:1:10  3025 48 — — Example 10 17 Preparation 2,000:1:100 30 40 48 1,2- 2:1Example 12 dichloroethane 18 Preparation 2,000:1:100 30 50 64 Toluene2:1 Example 13 19 Preparation 2,000:1:100 30 50 64 1,2- 2:1 Example 14dichloroethane

TABLE 4 PO Conversion Example Ratio Selectivity M_(n) PDI TON 6 82% 99%1,400 — 8,118 7 97% 99% 1,700 — 9,603 8 95% 99% 1,300 1.03 1,881 9 50%99% 3,000 1.12 990 10 67% 99% 3,300 1.22 1,327 11 59% 99% 1,900 1.151,168 12 66% 96% 1,200 — 6,336 13 38% 98% — — 745 14 20% 63% — — 252 1597% 97% — — 1,882 16 81% 99% 7,700 1.17 1,604 17 40% 70% — — 560 18 39%60% — — 468 19 100% 40% — — 800

Comparative Examples 1 to 4

Propylene oxide (PO), each binary catalyst system of (Salen)Co compound(combination of the catalyst represented by the following ChemicalFormula 23 and PPN⁺Cl⁻ represented by the following Chemical Formula24), and adipic acid were put into a high pressure stainless steelreactor at each molar ratio as shown in the following Table 5 and thereactor was completely fastened. Carbon dioxide (CO₂) having ultra-highpurity was slowly filled into the high pressure reactor and reaction wasperformed under predetermined pressure, operating temperature and timeas shown in the following Table 5. After the reaction was completed, thereaction was cooled and remaining carbon dioxide was slowly discharged.After the catalyst was removed, the reactant was dried in vacuo toobtain poly(propylene carbonate) and physical properties of the obtainedpoly(propylene carbonate) were shown in the following Table 6.

TABLE 5 Com- Reac- para- PO:Chemical tion tive Formula CO₂ Tem- ReactionExam- 23:PPN⁺Cl⁻:Adipic Pressure perature Time ple Catalyst acid (MolarRatio) (bar) (° C.) (hr) 1 Chemical 2,000:1:1:0 30 25 6 Formula 23 2Chemical 2,000:1:1:10 30 25 5 Formula 23 3 Chemical 2,000:1:1:20 30 25 5Formula 23 4 Chemical 2,000:1:1:30 30 25 5 Formula 23

TABLE 6 PO Comparative Conversion Example Ratio Selectivity M_(n) PDI 193%  96% 9,174 1.369 2 91% 100% 7,973 1.156 3 <5% — — — 4 — — — —

Comparative Examples 1 to 4 above disclose preparation of poly(alkylenecarbonate) by copolymerization of carbon dioxide/epoxide using amolecular weight regulator in the presence of the existing binarycatalyst system of (Salen)Co compound. According to the appreciationfrom Tables 5 and 6, as relative equivalent of the molecular weightregulator with respect to the catalyst system is increased, activity ofthe catalyst system was deteriorated, for example, PO conversion ratiowas decreased, and the like. In particular, it was appreciated that inwhich the relative equivalent of the molecular weight regulator is 20 ormore, which is a general level, PO conversion ratio was rapidlydecreased to be less than 5%, such that it was determined that activityof the catalyst system was not effectively maintained. Therefore, thereis a limitation in obtaining low molecular weight of copolymer atdesirable level by adding the molecular weight regulator at a generalquantitative level in the presence of the existing binary catalystsystem.

However, according to the preparation method of the present inventiondisclosed in Examples of Tables 1 to 4, it was appreciated that in thecase in which the relative equivalent of the molecular weight regulatoras compared to the catalyst system was 20 to 500 which is a generallevel, PO conversion ratio was obtained as an appropriate value. Inparticular, it was appreciated that even though the relative equivalentof the molecular weight regulator adopted 10 to 500 which was a broadrange, low molecular weight of copolymer at an appropriate level wasstably provided without a remarkable decrease in activity of thecatalyst.

In addition, it was appreciated that according to Examples of Tables 1to 4, the catalyst of the present invention effectively promoted thereaction even under a relatively low copolymerization temperaturecondition which was 20° C. to 50° C.

The invention claimed is:
 1. A complex represented by one of thefollowing Chemical Formula 10 or 11:

wherein in Chemical Formula 10, R⁸¹ and R⁸² identically representmethyl, ethyl, isopropyl, or tert-butyl; or a protonated groupidentically selected from a group consisting of Chemical Formula 2,Chemical Formula 3, Chemical Formula 5, Chemical Formula 6 and ChemicalFormula 7, below;

R⁸³ and R⁸⁴ identically represent methyl, ethyl, isopropyl, ortert-butyl; or a protonated group identically selected from a groupconsisting of Chemical Formula 2, Chemical Formula 3, Chemical Formula5, Chemical Formula 6 and Chemical Formula 7, above; wherein that a casewhere R⁸¹ and R⁸² identically represent methyl, ethyl, isopropyl, ortert-butyl; and simultaneously R⁸³ and R⁸⁴ identically represent methyl,ethyl, isopropyl, or tert-butyl is excluded; X₁ ⁻ is a halogen anion; a(C1-C20)alkylcarboxyl anion; a (C1-C20)alkylcarboxyl anion containingone or more selected from the group consisting of a halogen atom, anitrogen atom, an oxygen atom, a silicon atom, a sulfur atom and aphosphorus atom; a (C1-C20)alkylcarbonate anion; a(C1-C20)alkylcarbonate anion containing one or more selected from thegroup consisting of a halogen atom, a nitrogen atom, an oxygen atom, asilicon atom, a sulfur atom and a phosphorus atom; a(C1-C20)alkylcarbamate anion; or a (C1-C20)alkylcarbamate anioncontaining one or more selected from the group consisting of a halogenatom, a nitrogen atom, an oxygen atom, a silicon atom, a sulfur atom anda phosphorus atom; X₁ ⁻ may be coordinated to Co; Y₁ ⁻ is Cl⁻, Br⁻, BF₄⁻ or NO₃ ⁻; Y₂ ⁻² is SO₄ ⁻²; a is an integer obtained by adding 1 to thetotal number of monovalent cations included in protonated groups of R⁸¹to R⁸⁴; b is an integer of 1 or more, c is an integer of 0 or more, d isan integer of 0 or more, and b+c+2d=a is satisfied; Z₁, Z₃, Z₄, Z₆, Z₇,Z₈ and Z₉ are each independently a nitrogen atom or a phosphorus atom;Z₂ and Z₁₀ are each independently an oxygen atom, a sulfur atom or amethylene group (—CH₂—); n is an integer of 1 to 10; m is an integer of1 to 10; and R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R²¹, R²², R²³, R²⁴, R²⁵, R²⁶, R²⁷,R⁴¹, R⁴², R⁴³, R⁴⁴, R⁴⁵, R⁵¹, R⁵², R⁵³, R⁵⁴, R⁵⁵, R⁶¹, R⁶², R⁶³, R⁶⁴,R⁶⁵, R⁶⁶ and R⁶⁷ are each independently hydrogen; (C1-C20)alkyl;(C1-C20)alkyl containing one or more selected from among halogen,nitrogen, oxygen, silicon, sulfur and phosphorus; (C2-C20)alkenyl;(C2-C20)alkenyl containing one or more selected from among halogen,nitrogen, oxygen, silicon, sulfur and phosphorus;(C1-C20)alkyl(C6-C20)aryl; (C1-C20)alkyl(C6-C20)aryl containing one ormore selected from among halogen, nitrogen, oxygen, silicon, sulfur andphosphorus; (C6-C20)aryl(C1-C20)alkyl; (C6-C20)aryl(C1-C20)alkylcontaining one or more selected from among halogen, nitrogen, oxygen,silicon, sulfur and phosphorus; or a metalloid radical of Group 14 metalsubstituted with hydrocarbyl; two of R¹¹, R¹², R¹³, R¹⁴ and R¹⁵, two ofR²¹, R²², R²³, R²⁴, R²⁵, R²⁶ and R²⁷, two of R⁴¹, R⁴², R⁴³, R⁴⁴ and R⁴⁵,two of R⁵¹, R⁵², R⁵³, R⁵⁴ and R⁵⁵ or two of R⁶¹, R⁶², R⁶³, R⁶⁴, R⁶⁵, R⁶⁶and R⁶⁷ may be linked with each other to thereby form a ring; or

wherein in Chemical Formula 11, R⁸⁵ and R⁸⁶ identically representmethyl, ethyl, isopropyl, or tert-butyl; or are linked with each otherby a protonated group of Chemical Formula 8, below to thereby form aring;

R⁸⁷ and R⁸⁸ identically represent methyl, ethyl, isopropyl, ortert-butyl; or are linked with each other by a protonated group ofChemical Formula 8, above to thereby form a ring; wherein that a casewhere R⁸⁵ and R⁸⁶ identically represent methyl, ethyl, isopropyl, ortert-butyl; and simultaneously R⁸⁷ and R⁸⁸ identically represent methyl,ethyl, isopropyl, or tert-butyl is excluded; X₂ ⁻ is a halogen anion; a(C1-C20)alkylcarboxyl anion; a (C1-C20)alkylcarboxyl anion containingone or more selected from the group consisting of a halogen atom, anitrogen atom, an oxygen atom, a silicon atom, a sulfur atom and aphosphorus atom; a (C1-C20)alkylcarbonate anion; a(C1-C20)alkylcarbonate anion containing one or more selected from thegroup consisting of a halogen atom, a nitrogen atom, an oxygen atom, asilicon atom, a sulfur atom and a phosphorus atom; a(C1-C20)alkylcarbamate anion; or a (C1-C20)alkylcarbamate anioncontaining one or more selected from the group consisting of a halogenatom, a nitrogen atom, an oxygen atom, a silicon atom, a sulfur atom anda phosphorus atom; X₂ ⁻ may be coordinated to Co; Y₃ ⁻ is Cl⁻, Br⁻, BF₄⁻ or NO₃ ⁻; Y₄ ⁻² is SO₄ ⁻²; e is an integer obtained by adding 1 to thetotal number of monovalent cations included in protonated groups of R⁸⁵to R⁸⁸; f is an integer of 1 or more, g is an integer of 0 or more, h isan integer of 0 or more, and f+g+2h=e is satisfied; Z₁₁ and Z₁₂ are eachindependently a nitrogen atom or a phosphorus atom; n is an integer of 1to 10; m is an integer of 1 to 10; and R⁷¹, R⁷², R⁷³ and R⁷⁴ are eachindependently hydrogen; (C1-C20)alkyl; (C1-C20)alkyl containing one ormore selected from among halogen, nitrogen, oxygen, silicon, sulfur andphosphorus; (C2-C20)alkenyl; (C2-C20)alkenyl containing one or moreselected from among halogen, nitrogen, oxygen, silicon, sulfur andphosphorus; (C1-C20)alkyl(C6-C20)aryl; (C1-C20)alkyl(C6-C20)arylcontaining one or more selected from among halogen, nitrogen, oxygen,silicon, sulfur and phosphorus; (C6-C20)aryl(C1-C20)alkyl;(C6-C20)aryl(C1-C20)alkyl containing one or more selected from amonghalogen, nitrogen, oxygen, silicon, sulfur and phosphorus; or ametalloid radical of Group 14 metal substituted with hydrocarbyl; two ofR⁷¹, R⁷², R⁷³ and R⁷⁴ may be linked with each other to thereby form aring.
 2. The complex of claim 1, wherein it has a structure representedby one of the following Chemical Formulas 12 to 13, 15 to 16, 18 to 21:

wherein in Chemical Formula 12, R⁹¹ is methyl, ethyl, isopropyl ortert-butyl; R⁹² is (C1-C20)alkyl; Z₁₃ is an oxygen atom, a sulfur atomor a methylene group (—CH₂—); n is an integer of 1 to 10; X⁻ is Cl⁻ oran acetate anion (CH₃COO⁻); X⁻ may be coordinated to Co; Y₁ ⁻ is Cl⁻,Br⁻ or NO₃ ⁻; Y₂ ⁻² is SO₄ ⁻²; and b is an integer of 1 or more, c is aninteger of 0 or more, d is an integer of 0 or more, and b+c+2d=3 issatisfied;

wherein in Chemical Formula 13, R⁹³ is methyl, ethyl, isopropyl ortert-butyl; R⁹⁴, R⁹⁵ and R⁹⁶ are each independently (C1-C20)alkyl; n isan integer of 1 to 10; X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻); X⁻ maybe coordinated to Co; Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻; Y₂ ⁻² is SO₄ ⁻²; and bis an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=5 is satisfied;

wherein in Chemical Formula 15, R¹⁰¹ is methyl, ethyl, isopropyl ortert-butyl; R¹⁰², R¹⁰³, R¹⁰⁴, R¹⁰⁵ and R¹⁰⁶ are each independently(C1-C20)alkyl; n is an integer of 1 to 10; m is an integer of 1 to 10;X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻); X⁻ may be coordinated to Co; Y₁⁻ is Cl⁻, Br⁻ or NO₃ ⁻; Y₂ ⁻² is SO₄ ⁻²; and b is an integer of 1 ormore, c is an integer of 0 or more, d is an integer of 0 or more, andb+c+2d=5 is satisfied;

wherein in Chemical Formula 16, R¹⁰⁷ is methyl, ethyl, isopropyl ortert-butyl; R¹⁰⁸ and R¹⁰⁹ are each independently (C1-C20)alkyl; n is aninteger of 1 to 10; m is an integer of 1 to 10; X⁻ is Cl⁻ or an acetateanion (CH₃COO⁻); X⁻ may be coordinated to Co; Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻;Y₂ ⁻² is SO₄ ⁻²; and b is an integer of 1 or more, c is an integer of 0or more, d is an integer of 0 or more, and b+c+2d=3 is satisfied;

wherein in Chemical Formula 18, R¹¹⁴ is methyl, ethyl, isopropyl ortert-butyl; R¹¹⁵ is (C1-C20)alkyl; Z₁₄ is an oxygen atom, a sulfur atomor a methylene group (—CH₂—); n is an integer of 1 to 10; X⁻ is Cl⁻ oran acetate anion (CH₃COO⁻); X⁻ may be coordinated to Co; Y₁ ⁻ is Cl⁻,Br⁻ or NO₃ ⁻; Y₂ ⁻² is SO₄ ⁻²; and b is an integer of 1 or more, c is aninteger of 0 or more, d is an integer of 0 or more, and b+c+2d=3 issatisfied;

wherein in Chemical Formula 19, R¹¹⁶ is methyl, ethyl, isopropyl ortert-butyl; R¹¹⁷, R¹¹⁸ and R¹¹⁹ are each independently (C1-C20)alkyl;Z₁₅ is an oxygen atom, a sulfur atom or a methylene group (—CH₂—); n isan integer of 1 to 10; m is an integer of 1 to 10; X⁻ is Cl⁻ or anacetate anion (CH₃COO⁻); X⁻ may be coordinated to Co; Y₁ ⁻ is Cl⁻, Br⁻or NO₃ ⁻; Y₂ ⁻² is SO₄ ⁻²; and b is an integer of 1 or more, c is aninteger of 0 or more, d is an integer of 0 or more, and b+c+2d=5 issatisfied;

wherein in Chemical Formula 20, Z₁₆ is an oxygen atom, a sulfur atom ora methylene group (—CH₂—); n is an integer of 1 to 10; X⁻ is Cl⁻ or anacetate anion (CH₃COO⁻); X⁻ may be coordinated to Co; Y₁ ⁻ is Cl⁻, Br⁻or NO₃ ⁻; Y₂ ⁻² is SO₄ ⁻²; and b is an integer of 1 or more, c is aninteger of 0 or more, d is an integer of 0 or more, and b+c+2d=5 issatisfied;

wherein in Chemical Formula 21, R¹²⁰ is methyl, ethyl, isopropyl ortert-butyl; R¹²¹ is hydrogen, methyl, ethyl, isopropyl or tert-butyl; nis an integer of 1 to 10; X⁻ is Cl⁻ or an acetate anion (CH₃COO⁻); X⁻may be coordinated to Co; Y₁ ⁻ is Cl⁻, Br⁻ or NO₃ ⁻; Y₂ ⁻² is SO₄ ⁻²;and b is an integer of 1 or more, c is an integer of 0 or more, d is aninteger of 0 or more, and b+c+2d=3 is satisfied.
 3. A method ofpreparing poly(alkylene carbonate), comprising: copolymerizing carbondioxide and one or more epoxide compound selected from a groupconsisting of (C2-C20)alkylene oxide substituted or unsubstituted withhalogen, (C1-C20)alkyloxy, (C6-C20)aryloxy or(C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; (C4-C20)cycloalkylene oxidesubstituted or unsubstituted with halogen, (C1-C20)alkyloxy,(C6-C20)aryloxy or (C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; and(C8-C20)styrene oxide substituted or unsubstituted with halogen,(C1-C20)alkyloxy, (C6-C20)aryloxy, (C6-C20)ar(C1-C20)alkyl(aralkyl)oxyor (C1-C20)alkyl in the presence of the following compound representedby the following Chemical Formula 9 which is a molecular weightregulator:J(LH)_(c)  [Chemical Formula 9] wherein in Chemical Formula 9, J is C1to C60 hydrocarbyl c-valent radical with or without an ether group, anester group or an amine group; LH is —OH or —CO₂H; and c is an integerfrom 1 to 10, in which LH may be identical or different when c is 2 ormore, using the complex of claim 1, as a catalyst.
 4. The method ofclaim 3, wherein in the compound represented by Chemical Formula 9, c is1; and J is C1 to C60 hydrocarbyl radical with or without an ethergroup, an ester group, or an amine group.
 5. The method of claim 3,wherein in the compound represented by Chemical Formula 9, c is 2; and Jis C1 to C60 hydrocarbyl diradical with or without an ether group, anester group, or an amine group.
 6. The method of claim 5, wherein in thecompound represented by Chemical Formula 9, LH is —CO₂H; and J is—[CR₂]_(n)— (n is an integer of 0 to 20; and R which may be identical ordifferent represents hydrogen, methyl, ethyl, propyl, or butyl),para-phenylene, meta-phenylene, ortho-phenylene or 2,6-naphthalenediyl.7. The method of claim 5, wherein in the compound represented byChemical Formula 9, LH is —OH; and J is —[CR₂]_(n)— (n is an integer of0 to 20; and R which may be identical or different represents hydrogen,methyl, ethyl, propyl, or butyl), —CH₂CH₂N(R)CH₂CH₂— (R is C1 to C20hydrocarbyl) or —[CH₂CH(R)O]_(n)CH₂CH(R)— (n is an integer of 0 to 10;and R is hydrogen or methyl).
 8. The method of claim 5, wherein in thecompound represented by Chemical Formula 9, one of two LHs is —OH andthe other one is —CO₂H, and J is phenylene.
 9. The method of claim 3,wherein in the compound represented by Chemical Formula 9, c is 3; and Jis C1 to C60 hydrocarbyl triradical with or without an ether group, anester group, or an amine group.
 10. The method of claim 9, wherein inthe compound represented by Chemical Formula 9, LH is —CO₂H; and J is1,2,3-propanetriyl, 1,2,3-benzenetriyl, 1,2,4-benzenetriyl or1,3,5-benzenetriyl.
 11. The method of claim 3, wherein in the compoundrepresented by Chemical Formula 9, c is 4; and J is C1 to C60hydrocarbyl tetraradical with or without an ether group, an ester group,or an amine group.
 12. The method of claim 11, wherein in the compoundrepresented by Chemical Formula 9, LH is —CO₂H; and J is1,2,3,4-butanetetrayl or 1,2,4,5-benzenetetrayl.
 13. A method ofpreparing poly(alkylene carbonate), comprising: copolymerizing carbondioxide and one or more epoxide compound selected from a groupconsisting of (C2-C20)alkylene oxide substituted or unsubstituted withhalogen, (C1-C20)alkyloxy, (C6-C20)aryloxy or(C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; (C4-C20)cycloalkylene oxidesubstituted or unsubstituted with halogen, (C1-C20)alkyloxy,(C6-C20)aryloxy or (C6-C20)ar(C1-C20)alkyl(aralkyl)oxy; and(C8-C20)styrene oxide substituted or unsubstituted with halogen,(C1-C20)alkyloxy, (C6-C20)aryloxy, (C6-C20)ar(C1-C20)alkyl(aralkyl)oxyor (C1-C20)alkyl in the presence of the following compound representedby the following Chemical Formula 9 which is a molecular weightregulator, using the complex of claim 2 as a catalyst:J(LH)_(c)  [Chemical Formula 9] wherein in Chemical Formula 9, J is C1to C60 hydrocarbyl c-valent radical with or without an ether group, anester group or an amine group; LH is —OH or —CO₂H; and c is an integerfrom 1 to 10, in which LH may be identical or different when c is 2 ormore.